\input texinfo @c -*-texinfo-*-
@comment $Id: netcdf-install.texi,v 1.76 2010/02/27 14:35:49 ed Exp $
@c %**start of header
@setfilename netcdf-install.info
@settitle NetCDF Installation and Porting Guide
@setcontentsaftertitlepage
@c Combine the variable, concept, and function indices.
@synindex vr cp
@synindex fn cp
@c %**end of header

@c version-install.texi is automatically generated by automake and contains
@c defined variables VERSION, UPDATED, UPDATED-MONTH.
@include version-install.texi

@c This file contains shared definitions of some vars.
@include defines.texi

@ifinfo
@dircategory netCDF scientific data format
@direntry
* netcdf-install: (netcdf-install).   @value{i-man}
@end direntry
@end ifinfo

@titlepage
@title @value{i-man}
@subtitle NetCDF Version @value{VERSION}
@subtitle Last Updated @value{UPDATED}
@author Ed Hartnett, Russ Rew, John Caron
@author Unidata Program Center
@page
@vskip 0pt plus 1filll
@insertcopying
@end titlepage

@ifnottex
@node Top, Binaries, (dir), (dir)
@top NetCDF Installation and Porting Guide

This document describes how to build and install the netCDF library,
version @value{VERSION} on Unix and Windows systems. This document was
last updated on @value{UPDATED}.

The current stable release of netCDF, version 4.0, can be obtained
from the netCDF web page at @uref{@value{netcdf-url}}. Instructions
for installing the current stable release version of netCDF can be
found at @uref{@value{docs-url}}.

If netCDF does not build and pass all tests, and you don't find your
computing platform addressed in this document, then try
@uref{@value{netcdf-other-builds}} for reports of successful builds of
this package in environments to which we had no access.

For a brief introduction to the netCDF format and utilities see
@ref{Top, @value{tut-man},, netcdf-tutorial, @value{tut-man}}.

For a complete description of the netCDF format and utilities see 
@ref{Top, @value{n-man},, netcdf, @value{n-man}}.

Programming guides are available for C (@pxref{Top, @value{c-man},,
netcdf-c, @value{c-man}}), C++ (@pxref{Top, @value{cxx-man},,
netcdf-cxx, @value{cxx-man}}), Fortran 77 (@pxref{Top,
@value{f77-man},, netcdf-f77, @value{f77-man}}), and Fortran 90
(@pxref{Top, @value{f90-man},, netcdf-f90, @value{f90-man}}). All of
these documents are available from the netCDF-4 documentation page
@uref{@value{docs4-url}}.

Separate documentation for the netCDF Java library can be found at the
netCDF-Java website, @uref{@value{netcdf-java-url}}.

To learn more about netCDF, see the netCDF website
@uref{@value{netcdf-url}}.

@end ifnottex

@menu
* Binaries::                    Getting NetCDF Binaries
* Quick Instructions::          How to Build, Quickly
* Building on Unix::            How to Build, with Details
* Using::                       
* Building on Windows::         Building on Windows
* Build Problems::              What if it Doesn't Work?
* Combined Index::              Index of Concepts

@detailmenu
 --- The Detailed Node Listing ---

Building and Installing NetCDF on Unix Systems

* Requirements::                What's Needed to Build NetCDF
* Environment::                 Setting the Build Environment
* 64 Bit::                      Building on 64-bit Platforms
* parallel::                    Building with Parallel I/O
* Configure::                   Running configure
* Make::                        Running make
* Testing::                     Testing the Build
* Installation::                Installing Everything
* Platform Notes::              Specific Platform Notes
* Porting Notes::               Porting Notes for New Platforms
* Source::                      Working with the Source Code

Using NetCDF on Unix Systems

* Linker Flags::                
* Compiler Flags::              
* nc-config::                   

Building and Installing NetCDF on Windows

* Prebuilt DLL::                Getting the Prebuilt DLLs
* Installing DLL::              Installing the DLLs
* Visual Cplusplus::            Building with VC++ 6.0
* Using DLL::                   Using the DLLs with VC++ 6.0
* Building with NET::           Building with VC++ .NET 
* Using with NET::              Using with VC++ .NET

If Something Goes Wrong

* Usual Problems::              Problems which Occur Often
* Troubleshooting::             Finding the Problem
* Finding Help::                Getting Support
* Reporting Problems::          What to Send to Support

@end detailmenu
@end menu

@node Binaries, Quick Instructions, Top, Top
@chapter Installing the NetCDF Binaries
@cindex binary install
@cindex installing binary distribution
@cindex shared libraries, using

The easiest way to get netCDF is through a package management program,
such as rpm, yum, adept, and others. NetCDF is available from many
different repositories, including the default Red Hat and Ubuntu
repositories.

Another way to get netCDF is to get a pre-built binary
distribution. To get them, see @uref{@value{netcdf-binaries-url}}.

To install the binary distribution, uncompress and unpack the tar
file. You will end up with 4 subdirectories, lib, include, man, and
bin. 

The lib subdirectory holds the netCDF libraries (C, Fortran, and
C++). The include directory holds the necessary netcdf.h file (for C),
netcdf.inc (for Fortran), netcdfcpp.h (for C++), and the .mod files
(for Fortran 90). The bin directory holds the ncgen and ncdump
utilities, and the man directory holds the netCDF documentation.

You can have these directories anywhere you like, and use netCDF. But
when compiling a netCDF program, you will have to tell the linker
where to find the library (e.g. with the -L option of most C
compilers), and you will also have to tell the C pre-processor where
to find the include file (e.g. with the -I option).

If you are using shared libraries, you will also have to specify the
library location for run-time dynamic linking. See your compiler
documentation. For some general information see the netCDF FAQ ``How
do I use shared libraries'' at @uref{@value{netcdf-shared-faq-url}}.

@node Quick Instructions, Building on Unix, Binaries, Top
@chapter Quick Instructions for Installing NetCDF on Unix
@cindex quick unix instructions
@cindex shared libraries, building

Who has time to read long installation manuals these days?

When building netCDF-4, you must first decide whether to support the
use of HDF5 as a storage format. 

@section Building NetCDF Without HDF5

If you don't want netCDF-4/HDF5, then build like this:

@example
./configure --prefix=/home/ed/local --disable-netcdf-4
make check install
@end example

(Replace ``/home/ed/local'' with the name of the directory where
netCDF is to be installed.) 

If you get the message that netCDF installed correctly, then you are
done!

@section Building NetCDF With HDF5

If you want to use the HDF5 storage format, you must have the HDF5
1.8.4-patch1 release. You must also have the zlib compression library,
version 1.2.3 (or better). Both of these packages are available from
the netCDF-4 ftp site at @uref{@value{netcdf4-ftp-site}}.

Make sure you run ``make check'' for the HDF5 and zlib
distributions. They are very well-behaved distributions, but sometimes
the build doesn't work (perhaps because of something subtly
misconfigured on the target machine). If one of these libraries is not
working, netCDF will have serious problems.

Optionally, you can also build netCDF-4 with the szip 2.0 library
(a.k.a. szlib). NetCDF cannot create szipped data files, but can read
HDF5 data files that have used szip.

There are license restrictions on the use of szip, see the HDF5 web
page: @uref{@value{hdf5-szip-license-url}}. These license restrictions
seem to apply to commercial users who are writing data. (Data readers
are not restricted.) But here at NetCDF World Headquarters, in Sunny
Boulder, Colorado, there are no lawyers, only programmers, so please
read the szip documents for the license agreement to see how it
applies to your situation.

If you wish to use szip, get it from the HDF5 download page:
@uref{@value{hdf5-download-url}}.

If ``make check'' fails for either zlib or HDF5, the problem must be
resolved before the netCDF-4 installation can continue. For HDF5
problems, send email to the HDF5 help desk:
@value{hdf5-support-email}.

Build zlib like this:

@example
./configure --prefix=/home/ed/local
make check install
@end example

(If you want a shared library build of HDF5, you must set CFLAGS to
-fPIC before building zlib.)

Then you build HDF5, specifying the location of the zlib library:

@example
./configure --with-zlib=/home/ed/local --prefix=/home/ed/local --disable-shared 
make check install
@end example

This builds a static version of the HDF5 library. For a shared build,
don't use --disable-shared. For a shared build to work you must have
compiled zlib (and, optionally, szip) with CFLAGS=-fPIC. In this case
you may need to add the install directory to the LD_LIBRARY_PATH
environment variable. See the FAQ for more details on using
shared libraries: @uref{@value{netcdf-faq-url}}.

If you are building HDF5 with szip, then include the --with-szlib=
option, with the directory holding the szip library.

After HDF5 is done, build netcdf-4, specifying the location of the
HDF5, zlib, and (if built into HDF5) the szip libraries with the
--with-hdf5, --with-zlib, and --with-szlib option. (If they are all in
the same directory, you only need to use one of these options.)

@example
./configure --with-hdf5=/home/ed/local --prefix=/home/ed/local
make check install
@end example

The configure script will try to find necessary tools in your
path. When you run configure you may optionally use the --prefix
argument to change the default installation directory. For example,
the above examples install the zlib, HDF5, and netCDF-4 libraries in
/home/ed/local/lib, the header file in /home/ed/local/include, and the
utilities in /home/ed/local/bin.

The default install root is /usr/local (so there's no need to use the
prefix argument if you want the software installed there).

If HDF5 and zlib are found on your system, they will be used by netCDF
in the build. To prevent this use the --disable-netcdf-4 argument to
configure.

By default the netCDF configuration will build static libraries
only. For shared libraries as well, use the --enable-shared option to
configure.

To use netCDF-4 you must link to all the libraries, netCDF, HDF5,
zlib, and (if used with HDF5 build) szip. This will mean -L options to
your build for the locations of the libraries, and -l (lower-case L)
for the names of the libraries.

For example, one user reports that she can build other applications
with netCDF-4 by setting the LIBS envoronment variable:

@example
LIBS='-L/X/netcdf-4.0/lib -lnetcdf -L/X/hdf5-1.8.4/lib -lhdf5_hl -lhdf5 -lz -lm -L/X/szip-2.1/lib -lsz'
@end example

The nc-config command can be used to learn what options are needed for
the local netCDF installation.

@section Building with HDF4 Support

The netCDF-4 library can (since version 4.1) read HDF4 data files, if
they were created with the SD (Scientific Data) API. To enable this
feature, use the --enable-hdf4 option. The --with-hdf4= option may be
used to specify a location for the HDF4 library.

@node Building on Unix, Using, Quick Instructions, Top
@chapter Building and Installing NetCDF on Unix Systems
@cindex documents, latest version
@cindex binary releases
@cindex earlier netCDF versions

The latest version of this document is available at
@uref{@value{netcdf-install-url}}.

This document contains instructions for building and installing the
netCDF package from source on various platforms. Prebuilt binary
releases are (or soon will be) available for various platforms from
@uref{@value{netcdf-binaries-url}}.

A good general tutorial on how software is built from source on Linux
platforms can me found at
@uref{http://www.tuxfiles.org/linuxhelp/softinstall.html}.

@menu
* Requirements::                What's Needed to Build NetCDF
* Environment::                 Setting the Build Environment
* 64 Bit::                      Building on 64-bit Platforms
* parallel::                    Building with Parallel I/O
* Configure::                   Running configure
* Make::                        Running make
* Testing::                     Testing the Build
* Installation::                Installing Everything
* Platform Notes::              Specific Platform Notes
* Porting Notes::               Porting Notes for New Platforms
* Source::                      Working with the Source Code
@end menu

@node Requirements, Environment, Building on Unix, Building on Unix
@section Installation Requirements
@cindex installation requirements
@cindex large file tests requirements
@cindex extra_test requirements
@cindex extra_check requirements
@cindex enable-large-file-tests

If you wish to build from source on a Windows (Win32) platform,
different instructions apply. @xref{Building on Windows}.

Depending on the platform, you may need up to 25 Mbytes of free space
to unpack, build, and run the tests. You will also need a Standard C
compiler. If you have compilers for FORTRAN 77, FORTRAN 90, or C++,
the corresponding netCDF language interfaces may also be built and
tested. Compilers and associated tools will only be found if they are
in your path, or if you specify the path and compiler in the
appropriate environment variable. (Example for csh: setenv
CC /some/directory/cc).

If you want to run the large file tests, you will need about 13 GB of
free disk space, as some very large files are created. The created
files are immediately deleted after the tests complete. These large
file tests are not run unless the --enable-large-file-tests option is
used with configure. (The --with-temp-large option may also be used to
specify a directory to create the large files in).

Unlike the output from other netCDF test programs, each large test
program deletes its output before successfully exiting.

To use the netCDF-4 features you will also need to have a
HDF5-1.8.4-patch1 release installed. HDF5, in turn, must have been
built with zlib, version 1.2.3 (or better).

A tested version of HDF5 and zlib can be found at the netCDF-4 ftp
site at @uref{@value{netcdf4-ftp-site}}.

For more information about HDF5 see the HDF5 web site at
@uref{@value{hdf5-url}}. For more information about zlib see the zlib
web site at @uref{@value{zlib-url}}.

To use the DAP features you will also need to have a version of
libcurl (version 7.18.0 or later)
installed.
Depending on how this library
was built, you may also need zib (version 1.2.3 or later).
Information about libcurl may be obtained at
@uref{@value{curl-url}}.

@node Environment, 64 Bit, Requirements, Building on Unix
@section Specifying the Environment for Building

The netCDF configure script searches your path to find the compilers
and tools it needed. To use compilers that can't be found in your
path, set their environment variables.

The configure script will use gcc and associated GNU tools if they are
found. Many users, especially those with performance concerns, will
wish to use a vendor supplied compiler.

For example, on an AIX system, users may wish to use xlc (the AIX
compiler) in one of its many flavors. Set environment variables
before the build to achieve this.

For example, to change the C compiler, set CC to xlc (in sh: export
CC=xlc). (But don't forget to also set CXX to xlC, or else configure
will try to use g++, the GNU C++ compiler to build the netCDF C++
API. Similarly set FC to xlf90 so that the Fortran APIs are built
properly.)

By default, the netCDF library is built with assertions turned on. If
you wish to turn off assertions, set CPPFLAGS to -DNDEBUG (csh ex:
setenv CPPFLAGS -DNDEBUG).

If GNU compilers are used, the configure script sets CPPFLAGS to ``-g
-O2''. If this is not desired, set CPPFLAGS to nothing, or to whatever
other value you wish to use, before running configure.

For cross-compiles, the following environment variables can be used to
override the default fortran/C type settings like this (in sh):

@example
export NCBYTE_T=''integer(selected_int_kind(2))''
export NCSHORT_T=''integer*2''
export NF_INT1_T=''integer(selected_int_kind(2))''
export NF_INT2_T=''integer*2''
export NF_INT1_IS_C_SHORT=1
export NF_INT2_IS_C_SHORT=1
export NF_INT_IS_C_INT=1
export NF_REAL_IS_C_FLOAT=1
export NF_DOUBLEPRECISION_IS_C_DOUBLE=1
@end example

In this case you will need to run configure with
--disable-fortran-compiler-check and --disable-fortran-type-check.

@subsection Variable Description Notes 

@multitable @columnfractions .20 .20 .60

@item CC 
@tab C compiler 
@tab If you don't specify this, the configure script will try to
find a suitable C compiler. The default choice is gcc. If you wish to
use a vendor compiler you must set CC to that compiler, and set other
environment variables (as described below) to appropriate settings.

@item FC 
@tab Fortran compiler (if any) 
@tab If you don't specify this, the configure script will try to find a
suitable Fortran and Fortran 77 compiler. Set FC to "" explicitly, or
provide the --disable-f77 option to configure, if no Fortran interface
(neither F90 nor F77) is desired. Use --disable-f90 to disable the
netCDF Fortran 90 API, but build the netCDF Fortran 77 API.

@item F77
@tab Fortran 77 compiler (if any) 
@tab Only specify this if your platform explicitly needs a different
Fortran 77 compiler. Otherwise use FC to specify the Fortran compiler.
If you don't specify this, the configure script will try to find a
suitable Fortran compiler. For vendor compilers, make sure you're
using the same vendor's Fortran 90 compiler. Using Fortran compilers
from different vendors, or mixing vendor compilers with g77, the GNU
F77 compiler, is not supported and may not work.

@item CXX 
@tab C++ compiler 
@tab If you don't specify this, the configure script will try to find a
suitable C++ compiler. Set CXX to "" explicitly, or use the
--disable-cxx configure option, if no C++ interface is desired. If
using a vendor C++ compiler, use that vendor's C compiler to compile
the C interface. Using different vendor compilers for C and C++ may
not work.

@item CFLAGS 
@tab C compiler flags 
@tab "-O" or "-g", for example.

@item CPPFLAGS 
@tab C preprocessor options 
@tab "-DNDEBUG" to omit assertion checks, for example.

@item FCFLAGS 
@tab Fortran 90 compiler flags 
@tab "-O" or "-g", for example. These flags will be used for FORTRAN
90. If setting these you may also need to set FFLAGS for the FORTRAN
77 test programs.

@item FFLAGS 
@tab Fortran 77 compiler flags 
@tab "-O" or "-g", for example. If you need to pass the same arguments
to the FORTRAN 90 build, also set FCFLAGS.

@item CXXFLAGS 
@tab C++ compiler flags 
@tab "-O" or "-g", for example. 

@item ARFLAGS, NMFLAGS, FPP, M4FLAGS, LIBS, FLIBS, FLDFLAGS  
@tab Miscellaneous 
@tab One or more of these were needed for some platforms, as specified
below. Unless specified, you should not set these environment
variables, because that may interfere with the configure script.

@item HDF5DIR
@tab configure option
@tab Set this to the directory you wish to specify in the --with-hdf5
argument of configure.

@end multitable

The section marked Tested Systems below contains a list of systems on
which we have built this package, the environment variable settings we
used, and additional commentary.

@node 64 Bit, parallel, Environment, Building on Unix
@section Building on 64 Bit Platforms
@cindex 64-bit platforms
@cindex SunOS 64-bit build
@cindex AIX 64-bit build

The compiler options for SunOS, Irix, and AIX are listed below. The
zlib and HDF5 libraries must also be built with 64-bit options.

@table @code

@item AIX
Set -q64 option in all compilers, and set NMFLAGS to -X64, and ARFLAGS
to '-X64 cru'. Alternatively, set environment variable OBJECT_MODE to
64 before running configure.

@item IRIX 
Set the -64 option in all compilers.

@item SunOS
Use the -xarch=v9 or -m64 flag on all compilers for Sparc, or -m64 on
x86 platforms.

@end table

@node parallel, Configure, 64 Bit, Building on Unix
@section Building on Platforms with Parallel I/O
@cindex parallel platforms
@cindex MPICH2
@cindex --enable-parallel-tests

NetCDF makes available the parallel I/O features of HDF5 and the
parallel-netcdf libraries, allowing parallel I/O from netCDF-4 linked
programs.

@subsection Building HDF5 for Parallel I/O

For parallel I/O to work, HDF5 must be installed with
--enable-parallel, and an MPI library (and related libraries) must be
made available to the HDF5 configure. This can be accomplished with
the mpicc wrapper script, in the case of MPICH2.

The following works to build HDF5 with parallel I/O on our netCDF
testing system:

@example
CC=mpicc ./configure --enable-parallel --prefix=/shecky/local_par --with-zlib=/shecky/local_par --disable-shared && make check install
@end example

@subsection The parallel-netcdf Library

Optionally, the parallel-netcdf library should also be installed, and
the replacement for pnetcdf.h should be copied from
ftp://ftp.unidata.ucar.edu/pub/netcdf/contrib/pnetcdf.h.

@subsection Building NetCDF

To build netCDF with parallel I/O, build as usual, but point the
configure at a version of HDF5 that has been built for parallel I/O.

@example
FC=mpif90 CXX=mpicxx CC=mpicc ./configure --with-hdf5=/shecky/local_par
make check install
@end example

To enable the parallel tests, specify --enable-parallel-tests as an
option to configure. These tests will be run as mpiexec calls. This
may not be appropriate on all systems, especially those which use some
queue for jobs. 

To use parallel-netcdf to perform parallel I/O on classic and 64-bit
offset files, use the --enable-pnetcdf option (and, optionally, the
--with-pnetcdf option to specify a location for the parallel-netcdf
library).

@example
FC=mpif90 CXX=mpicxx CC=mpicc ./configure --with-hdf5=/shecky/local_par --enable-pnetcdf --with-pnetcdf=/shecky/local/pnetcdf
make check install
@end example

For parallel builds the netCDF examples are not built. This is to
avoid cluttering them with MPI_Init/Finalize calls.

@node Configure, Make, parallel, Building on Unix
@section Running the configure Script
@cindex configure, running
@cindex running configure
@cindex install directory
@cindex prefix argument of configure
@cindex config.log

To create the Makefiles needed to build netCDF, you must run the
provided configure script. Go to the top-level netCDF directory.

Decide where you want to install this package. Use this for the
"--prefix=" argument to the configure script below. The default
installation prefix is ``/usr/local,'' which will install the
package's files in usr/local/bin, usr/local/lib, and
usr/local/man. The default can be overridden with the --prefix
argument to configure.

Here's how to execute the configure script with a different
installation directory:

@example
    ./configure --prefix=/whatever/you/decided --with-hdf5=/home/ed/local
@end example

The above would cause the netCDF libraries to be installed in
/whatever/you/decided/lib, the header files in
/whatever/you/decided/include, the utilities (ncdump/ncgen) in
/whatever/you/decided/bin, and the man pages in
/whatever/you/decided/man.

The --with-hdf5 option tells configure the location of the HDF5 and
zlib libraries. HDF5 must be version 1.8.4-patch1 or better, and the
HDF5 library must have been built with zlib, version 1.2.3 or better.

If the configure script finds HDF5 in the system directories, it will
(attempt to) build the netCDF-4 enhanced features. To turn this off
use the --disable-netcdf-4 option.

There are other options for the configure script. The most useful ones
are listed below. Use the --help option to get the full list.

@vtable @code

@item --prefix
Specify the directory under which netCDF will be
installed. Subdirectories lib, bin, include, and man will be created
there, if they don't already exist.

@item --disable-netcdf-4
Turn off netCDF-4 features, even if HDF5 library is found.

@item --with-hdf5=/location
Specify the location of the HDF5 library.

@item --with-zlib=/location
Specify the location of the zlib library. NetCDF-4 requires that HDF5
be built with zlib, for variable compression.

@item --with-szlib=/location
Optionally specify the location of the szlib (a.k.a. szip)
library. (HDF5 must have been built with szlib support.)

@item --enable-shared
Build shared libraries (as well as static) on platforms which support
them.

@item --enable-dap
Enable DAP support. This flag is set by default
if the configure script can locate a usable
instance of the curl-config program.
The curl-config program can be specified explicitly
using --with-curl-config=/some/path/curl-config,
or configure will attempt some heuristics to locate
the curl-config program; typically by checking
the PATH environment variable.
If the flag --enable-dap flag is not set to either --enable-dap or
--disable-dap, and a usable curl library can be found,
then DAP support will be enabled by default.
Note that when DAP is enabled, this can be tested for
in a configure script by looking for the function
``nc__opendap''.

@item --with-curl-config
This flag may be used to specify the curl-config program
so that DAP support can be enabled.
Note that it should specify the actual program
using something like --with-curl-config=/some/path/curl-config.

@item --enable-dap-remote-tests
If DAP support is enabled, then remote tests are
run that utilize the test server at opendap.org.
This option is enabled by default.
Since that server may be inaccessible
for a variety of reasons, these tests may fail,
in which case this flag should be disabled.

@item --enable-dap-long-tests
If --enable-dap-remote-tests is enabled, then this
flag can also be enabled to add extra tests that may
take signficant time to execute. 
This flag is off by default.

@item --enable-hdf4
Turns on the HDF4 read layer. This reads HDF4 files created with the
SD (Scientific Data) API of HDF4. If the HDF4 library is in a
different directory, use the --with-hdf4= option to specify its
location.

@item --with-hdf4=/your/hdf4/location
Use the --with-hdf4 option to specify a location for the HDF4
directory, if it is not in any of the system directories, nor in the
same directory as HDF5.

@item --enable-hdf4-file-tests
Causes make check to use wget to fetch some HDF4 data files from the
Unidata FTP server, and check that they are properly understood. This
is done as part of automatic netCDF testing, and should not be done by
users.

@item --enable-pnetcdf
Allows parallel I/O with classic and 64-bit offset format files, using
the parallel-netcdf (formerly pnetcdf) library from
Argonne/Northwestern. The parallel-netcdf library must be installed,
and a specially modified pnetcdf.h must be used. (Get it at
ftp://ftp.unidata.ucar.edu/pub/netcdf/user/contrib/pnetcdf.h)

@item --with-udunits
Builds UDUNITS2 as well as netCDF. The UDUNITS2 package supports units
of physical quantities (e.g., meters, seconds). Specifically, it
supports conversion between string and binary representations of
units, arithmetic manipulation of units, and conversion of numeric
values between compatible units. For more information about UDUNITS,
see: http://www.unidata.ucar.edu/software/udunits/

@item --disable-largefile
This omits OS support for large files (i.e. files larger than 2 GB). 

@item --disable-fortran
Turns off Fortran 77 and Fortran 90 API. (Same as --disable-f77.)

@item --disable-f77
This turns off building of the F77 and F90 APIs. (The F90 API cannot
be built without the F77 API). This also disables some of the
configure tests that relate to fortran, including the test of the F90
compiler. Setting the environment variables FC or F77 to NULL will
have the same effect as --disable-f77.

@item --disable-f90
This turns off the building of the F90 API. Setting the environment
variable F90 to null for configure will have the same effect.

@item --disable-cxx 
This turns off the building of the C++ API. Setting the environment
variable CXX to null for configure will have the same effect.

@item --disable-v2
This turns of the V2 API. The V2 API is completely replaced with the
V3 API, but is usually built with netCDF for backwards compatibility,
and also because the C++ API depends on the V2 API. Setting this has
the effect of automatically turning off the CXX API, as if
--disable-cxx had also been specified.

@item --enable-cxx4
Turns on the new C++ API, which is currently under development, and
will expose the full expanded model in the C++ API. The cxx4 API is
experiemental, unfinished, and untested. It is provided for
experiemental purposes only.

@item --enable-large-file-tests
Turn on tests for large files. These tests create files over 2 GB in
size, and need about 13 GB of free disk space to run. These files are
deleted after the test successfully completes. They will be created in
the netCDF nc_test directory, unless the --with-temp-large option is
used to specify another location (see below).

@item --with-temp-large
Normally large files are not created during the netCDF build, but they
will be if --enable-large-file-tests is specified (see above). In that
case, this configure parameter can be used to specify a location to
create these large files, for example: --with-large-files=/tmp/ed.

@item --enable-benchmarks
Turn on tests of the speed of various netCDF operations. Some of these
operations take a long time to run (minutes, on a reasonable
workstation).

@item --enable-valgrind-tests
Causes some tests to be re-run under valgrind, the memory testing
tool. Valgrind must be present for this to work. Also HDF5 must be
built with --enable-using-memchecker, and netCDF must be compiled
without optimization (at least on the Unidata test platform where this
is tested). The valgrind tests are run by shell script
libsrc4/run_valgrind_tests.sh. It simply reruns the test programs in
that directory, using valgrind, and with settings such that any error
reported by valgrind will cause the ``make check'' to fail.

@item --disable-fortran-compiler-check
Normally the netCDF configure checks the F77 and F90 compilers with
small test programs to see if they work. This is very helpful in
supporting netCDF installations on different machines, but won't work
with cross-compilation. Use the --disable-fortran-compiler-check to
turn off the fortran compiler tests, and just assume that the
compilers will work.

@item --disable-fortran-type-check
The netCDF configure compiles and runs some programs to test fortran
vs. C type sizes. Setting this option turns off those test, and uses a
set of default values (which can be overridden by environment
variables @pxref{Environment}).

@item --disable-compiler-recover
Normally, if the netCDF configure finds a F90 compiler, and it fails
to build the test program described in --disable-f90-check, it will
print a warning, and then continue to build without the F90 API, as if
the user has specified --disable-f90. With the
--disable-compiler-recover option set, it will not continue, but will
just stop if the fortran 90 compiler doesn't work. This is useful for
automatic testing, where we want the tests to fail if something causes
the fortran compiler to break.

@item --disable-examples
Starting with version 3.6.2, netCDF comes with some examples in the
``examples'' directory. By default, the examples are all built during
a ``make check'' unless the --disable-examples option is provided.

@item --enable-separate-fortran 
This will cause the Fortran 77 and Fortran 90 APIs to be built into
their own separate library, instead of being included in the C
library. This is useful for supporting more than one fortran compiler
with the same netCDF C library. This is turned on by default for
shared library builds.

@item --enable-extra-tests
This option may turn on tests which are known to fail (i.e. bugs that
we are currently working to fix).

@item --with-default-chunk-size
Change the size (in bytes) that will be used as a target size when
computing default chunksizes for netCDF-4/HDF5 chunked variables.

@item --default-chunks-in-cache
Change the number of chunks that are accomodated in the per-variable
chunk caches that are used by default.

@item --max-default-cache-size
Change the maximum size of the per-variable chunk caches that are used
by default.

@item --with-chunk-cache-size
Change the size of the default file-level chunk cache size that will
be used when opening netCDF-4/HDF5 files.

@item --with-chunk-cache-nelems
Change the size of the default file-level chunk cache number of
elements that will be used when opening netCDF-4/HDF5 files. Should be
a prime number.

@item --with-chunk-cache-preemption
Change the default preemption of the file-level chunk cache that will
be used when opening netCDF-4/HDF5 files. Must be a number between 0
and 1 (inclusive).

@end vtable

The configure script will examine your computer system -- checking for
attributes that are relevant to building the netCDF package. It will
print to standard output the checks that it makes and the results that
it finds.

The configure script will also create the file "config.log", which
will contain error messages from the utilities that the configure
script uses in examining the attributes of your system. Because such
an examination can result in errors, it is expected that "config.log"
will contain error messages. Therefore, such messages do not
necessarily indicate a problem (a better indicator would be failure of
the subsequent "make"). One exception, however, is an error message in
"config.log" that indicates that a compiler could not be started. This
indicates a severe problem in your compilation environment -- one that
you must fix. If this occurs, configure will not complete and will
exit with an error message telling you about the problem.

@node Make, Testing, Configure, Building on Unix
@section Running make
@cindex make, running
@cindex running make

Run "make". This will build one or more netCDF libraries. It will
build the basic netCDF library libnetcdf.a. If you have Fortran 77 or
Fortran 90 compilers, then the Fortran library will also be built
(libnetcdff.a). If you have a C++ compiler, then the C++ interface
will be built (libnetcdf_c++.a.) 

A ``make'' will also build the netCDF utilities ncgen(1) and
ncdump(1).

Run make like this:
@example
make
@end example

@node Testing, Installation, Make, Building on Unix
@section Testing the Build
@cindex tests, running
@cindex make test
@cindex make check
@cindex large file tests
@cindex enable-large-file-tests
@cindex testing large file features
@cindex TEMP_LARGE
@cindex make slow_check
@cindex make lfs_test
@cindex make all_large_tests

Run ``make check'' to verify that the netCDF library and executables
have been built properly (you can instead run ``make test'' which does
the same thing). 

A make check will build and run various test programs that test the C,
Fortran, and C++ interfaces as well as the "ncdump" and "ncgen"
utility programs. 

Lines in the output beginning with "***" report on success or failure
of the tests; any failures will be reported before halting the
test. Compiler and linker warnings during the testing may be ignored.

Run the tests like this:

@example
make check
@end example

If you plan to use the 64-bit offset format (introduced in version
3.6.0) or the netCDF-4/HDF5 format to create very large files
(i.e. with variables larger than 2 GB), you should probably specify the
--enable-large-file-tests to configure, which tests the large file
features. You must have 13 GB of free disk space for these tests to
successfully run.

If you are running the large file tests, you may wish to use the
--with-temp-large option to specify a temporary directory for the
large files. (You may also set the environment variable TEMP_LARGE
before running configure).

The default is to create the large files in the nc_test subdirectory
of the netCDF build.

Run the large file tests like this:

@example
./configure --enable-large-file-tests --with-temp-large=/home/ed/tmp
make check
@end example

All of the large files are removed on successful completion of
tests. If the test fails, you may wish to make sure that no large
files have been left around.

If any of the the large file tests test fail, check to ensure that
your file system can handle files larger than 2 GiB by running the
following command:

@example
	dd if=/dev/zero bs=1000000 count=3000 of=$(TEMP_LARGE)/largefile
@end example

If your system does not have a /dev/zero, this test will fail. Then
you need to find some other way to create a file larger than 2 GiB to
ensure that your system can handle them.

@xref{Build Problems}.

@node Installation, Platform Notes, Testing, Building on Unix
@section Installing NetCDF
@cindex make install
@cindex installing netCDF
@cindex _LARGE_FILES, on AIX
@cindex OBJECT_MODE, on AIX

To install the libraries and executables, run "make install". This
will install to the directory specified in the configure step.

Run the installation like this:

@example
make install
@end example

The install will put files in the following subdirectories of the
directory you provided as a prefix, creating the subdirectories if
needed:

@table @code

@item lib
Libraries will be installed here. If static libraries are built,
without separate fortran libraries, then libnetcdf.a and libnetcdf.la
will be installed. If the C++ API is built, libnetcdf_c++.a and
libnetcdf_c++.la will be added. If separate fortran libraries are
built, libnetcdff.a and libnetcdff.la will also be added. 

Static library users should ignore the .la files, and link to the .a
files.

Shared library builds will add some .so files to this directory, as
well.

@item include
Header files will be installed here. The C library header file is
netcdf.h. If the C++ library is built, ntcdfcpp.h, ncvalues.h and
netcdf.hh will be installed here. If the F77 API is built, netcdf.inc
will be copied here. If the F90 API is built, the netcdf.mod and
typesizes.mod files will be copied here as well.

@item bin
Utilities ncdump and ncgen will be installed here.

@item man
The ncdump/ncgen man pages will be installed in subdirectory man1, and
the three man pages netcdf.3, netcdf_f77.3, and netcdf_f90.3 will be
installed in the man3 subdirectory.

@item share
If the configure is called with the --enable-docs option, the netCDF
documentation set will be built, and will be installed under the share
directory, under the netcdf subdirectory. This will include
postscript, PDF, info and text versions of all netCDF manuals. These
manuals are also available at the netCDF web site.

@end table

Try linking your applications. Let us know if you have problems
(@pxref{Reporting Problems}). 

@node Platform Notes, Porting Notes, Installation, Building on Unix
@section Platform Specific Notes
@cindex Cygwin, building with
@cindex AIX, building on
@cindex HPUX, building on
@cindex Irix, building on
@cindex Linux, building on
@cindex Macintosh, building on
@cindex OSF1, building on
@cindex SunOS, building on
@cindex Intel fortran
@cindex fortran, Intel
@cindex Portland Group fortran
@cindex fortran, Portland Group

The following platform-specific note may be helpful when building and
installing netCDF. Consult your vendor manuals for information about
the options listed here. Compilers can change from version to version;
the following information may not apply to your platform.

Full output from some of the platforms of the test platforms for
netCDF @value{VERSION} can be found at @uref{@value{netcdf-builds}}.

@subsection AIX

We found the vendor compilers in /usr/vac/bin, and included this 
in our PATH. Compilers were xlc, xlf, xlf90, xlC.

The F90 compiler requires the qsuffix option to believe that F90 code
files can end with .f90. This is automatically turned on by configure
when needed:

@example
    FCFLAGS=-qsuffix=f=f90
@end example

We had to use xlf for F77 code, and xlf90 for F90 code.

To compile 64-bit code, set the appropriate environment variables
(documented below).

The environment variable OBJECT_MODE can be set to 64, or use the -q64
option on all AIX compilers by setting CFLAGS, FFLAGS, and CXXFLAGS to
-q64.

The following is also necessary on an IBM AIX SP system for 64-bit
mode:
@example
    ARFLAGS='-X64 cru'
    NMFLAGS='-X64'
@end example

There are thread-safe versions of the AIX compilers. For example,
xlc_r is the thread-safe C compiler. To use thread-safe compilers,
override the configure script by setting CC to xlc_r; similarly for FC
and CXX.

For large file support, AIX requires that the macro _LARGE_FILES be
defined. The configure script does this using
AC_SYS_LARGEFILES. Unfortunately, this misfires when OBJECT_MODE is
64, or the q64 option is used. The netCDF tries to fix this by turning
on _LARGE_FILES anyway in these cases.

The GNU C compiler does not mix successfully with the AIX fortran
compilers. 

@subsection Cygwin

NetCDF builds under Cygwin tools on Windows just as with Linux.

@subsection HPUX

The HP Fortran compiler (f77, a.k.a. fort77, also f90) requires FLIBS
to include -lU77 for the fortran tests to work. The configure script
does this automatically.

For the c89 compiler to work, CPPFLAGS must include
-D_HPUX_SOURCE. This isn't required for the cc compiler. The configure
script adds this as necessary.

For large file support, HP-UX requires _FILE_OFFSET_BITS=64. The
configure script sets this automatically.

The HPUX C++ compiler doesn't work on netCDF code. It's too old for
that. So either use GNU to compile netCDF, or skip the C++ code by
setting CXX to '' (in csh: setenv CXX '').

Building a 64 bit version may be possible with the following settings:
@example
    CC=/bin/cc
    CPPFLAGS='-D_HPUX_SOURCE -D_FILE_OFFSET_BITS=64'    # large file support
    CFLAGS='-g +DD64'                           # 64-bit mode
    FC=/opt/fortran90/bin/f90                   # Fortran-90 compiler
    FFLAGS='-w +noppu +DA2.0W'                  # 64-bit mode, no "_" suffixes
    FLIBS=-lU77
    CXX=''                                      # no 64-bit mode C++ compiler
@end example

Sometimes quotas or configuration causes HPUX disks to be limited to 2
GiB files. In this cases, netCDF cannot create very large
files. Rather confusingly, HPUX returns a system error that indicates
that a value is too large to be stored in a type. This may cause
scientists to earnestly check for attempts to write floats or doubles
that are too large. In fact, the problem seems to be an internal
integer problem, when the netCDF library attempts to read beyond the 2
GiB boundary. To add to the confusion, the boundary for netCDF is
slightly less than 2 GiB, since netCDF uses buffered I/O to improve
performance.

@subsection Irix

A 64-bit version can be built by setting the appropriate environment
variables.

Build 64-bit by setting CFLAGS, FFLAGS, and CXXFLAGS to -64.

On our machine, there is a /bin/cc and a /usr/bin/cc, and the -64
option only works with the former.

@subsection Linux

The f2cFortran flag is required with GNU fortran:
@example
    CPPFLAGS=-Df2cFortran
@end example

For Portland Group Fortran, set pgiFortran instead:
@example
    CPPFLAGS=-DpgiFortran
@end example

Portland Group F90/F95 does not mix with GNU g77.

The netCDF configure script should notice which fortran compiler is
being used, and set these automatically.

For large file support, _FILE_OFFSET_BITS must be set to 64. The
netCDF configure script should set this automatically.

@subsection Macintosh

The f2cFortran flag is required with GNU fortran
(CPPFLAGS=-Df2cFortran). The NetCDF configure script should and set
this automatically.

For IBM compilers on the Mac, the following may work (we lack this
test environment):
@example
    CC=/usr/bin/cc
    CPPFLAGS=-DIBMR2Fortran
    F77=xlf
    FC=xlf90
    FCFLAGS=-qsuffix=cpp=f90
@end example

@subsection OSF1

NetCDF builds out of the box on OSF1.

@subsection SunOS

PATH should contain /usr/ccs/bin to find make, nm, ar, etc.

For large file support, _FILE_OFFSET_BITS must be 64, also
_LARGEFILE64_SOURCE and _LARGEFILE_SOURCE must be set. Configure will
turn this on automatically for netCDF, but not for HDF5. So when
building HDF5, set these variables before running configure, or HDF5
will not be capable of producing large files.

To compile in 64-bit mode, set -m64 (formerly -xarch=v9, which works
on SPARC platforms only) on all compilers (i.e. in CFLAGS, FFLAGS,
FCFLAGS, and CXXFLAGS).

When compiling with GNU Fortran (g77), the -Df2cFortran flag is
required for the Fortran interface to work. The NetCDF configure
script turns this on automatically if needed.

@subsection Handling Fortran Compilers

Commercial fortran compilers will generally require at least one flag
in the CPPFLAGS variable. The netCDF configure script tries to set
this for you, but won't try if you have used --disable-flag-setting,
or if you have already set CPPFLAGS, CFLAGS, CXXFLAGS, FCFLAGS, or
FFLAGS yourself.

The first thing to try is to set nothing and see if the netCDF
configure script finds your fortran compiler, and sets the correct
flags automatically.

If it doesn't find the correct fortran compiler, you can next try
setting the FC environment variable to the compiler you wish to use,
and then see if the configure script can set the correct flags for
that compiler.

If all that fails, you must set the flags yourself.

The Intel compiler likes the pgiFortran flag, as does the Portland
Group compiler. (Automatically turned on if your fortran compiler is
named ``ifort'' or ``pgf90'').

Alternatively, Intel has provided a web page on ``Building netCDF with
the Intel compilers'' at
@uref{http://www.intel.com/support/performancetools/sb/CS-027812.htm},
providing instructions for building netCDF (without using the
pgiFortran flag).

The Portland Group also has a ``PGI Guide to NetCDF'' at
@uref{http://www.pgroup.com/resources/netcdf/netcdf362_pgi71.htm}.

@node Porting Notes, Source, Platform Notes, Building on Unix
@section Additional Porting Notes
@cindex GNU make
@cindex porting notes, additional
@cindex CRAY, porting to
@cindex ncconfig.h
@cindex ncconfig.in
@cindex ncconfig.inc
@cindex ncio
@cindex ncx.m4
@cindex ffio.c
@cindex posixio.c
@cindex big endian
@cindex little endian

The configure and build system should work on any system which has a
modern "sh" shell, "make", and so on. The configure and build system
is less portable than the "C" code itself, however. You may run into
problems with the "include" syntax in the Makefiles. You can use GNU
make to overcome this, or simply manually include the specified files
after running configure.

Instruction for building netCDF on other platforms can be found at
@uref{@value{netcdf-other-builds}}. If you build netCDF on a new
platform, please send your environment variables and any other
important notes to @value{netcdf-support-email} and we will add the
information to the other builds page, with a credit to you.

If you can't run the configure script, you will need to create
config.h and fortran/nfconfig.inc. Start with ncconfig.in and
fortran/nfconfig.in and set the defines as appropriate for your
system.

Operating system dependency is isolated in the "ncio" module. We
provide two versions. posixio.c uses POSIX system calls like "open()",
"read()" and "write().  ffio.c uses a special library available on
CRAY systems. You could create other versions for different operating
systems. The program "t_ncio.c" can be used as a simple test of this
layer.

Note that we have not had a Cray to test on for some time. In
particular, large file support is not tested with ffio.c.

Numerical representation dependency is isolated in the "ncx"
module. As supplied, ncx.m4 (ncx.c) supports IEEE floating point
representation, VAX floating point, and CRAY floating
point. BIG_ENDIAN vs LITTLE_ENDIAN is handled, as well as various
sizes of "int", "short", and "long". We assume, however, that a "char"
is eight bits.

There is a separate implementation of the ncx interface available as
ncx_cray.c which contains optimizations for CRAY vector
architectures. Move the generic ncx.c out of the way and rename
ncx_cray.c to ncx.c to use this module. By default, this module does
not use the IEG2CRAY and CRAY2IEG library calls. When compiled with
aggressive in-lining and optimization, it provides equivalent
functionality with comparable speed and clearer error semantics. If
you wish to use the IEG library functions, compile this module with
-DUSE_IEG.

@node Source,  , Porting Notes, Building on Unix
@section Contributing to NetCDF Source Code Development

Most users will not be interested in working directly with the netCDF
source code. Rather, they will write programs which call netCDF
functions, and delve no further. However some intrepid users may wish
to dig into the netCDF code to study it, to try and spot bugs, or to
make modifications for their own purposes.

To work with the netCDF source code, several extra utilities are
required to fully build everything from source. If you are going to
modify the netCDF source code, you will need some or all of the
following Unix tools.

@ftable @code

@item m4
Macro processing language used heavily in libsrc, nc_test. Generates
(in these cases) C code from m4 source. Version 1.4 works fine with
release 3.5.1 through 3.6.2. 

@item flex and yacc
Used in ncgen directory to parse CDL files. Generates C files from .y
and .l files. You only need to use this to modify ncgen's understanding of
CDL grammar.

@item makeinfo
Generates all documentation formats (except man pages) from texinfo
source. I'm using makeinfo version 4.8, as of release 3.6.2. If you
have trouble with makeinfo, upgrade to this version and try again. You
only need makeinfo if you want to modify the documentation.

@item tex
Knuth's venerable typesetting system. The version I am running (for
netCDF release 3.6.2) is TeX 3.141592 (Web2C 7.5.4). I have found that
some recent installations of TeX will not build the netCDF
documentation - it's not clear to me why.

The user generally will just want to download the latest version of
netCDF documents at the netCDF website. @uref{@value{docs-url}}.

@item autoconf
Generates the configure script. Version 2.59 or later is required.

@item automake
Since version 3.6.2 of netCDF, automake is used to generate the
Makefile.in files needed by the configure script to build the
Makefiles.

@item libtool 
Since version 3.6.2 of netCDF, libtool is used to help generate shared
libraries platforms which support them. Version 2.1a of libtool is
required.

@item sed
This text processing tool is used to process some of the netCDF
examples before they are included in the tutorial. This is only needed
to build the documentation, which the user generally will not need to
do.

@end ftable

NetCDF has a large and enterprising user community, and a long history
of accepting user modifications into the netCDF code base. Examples
include the 64-bit offset format, and the F90 API.

All suggested changes and additions to netCDF code can be sent to
@value{netcdf-support-email}.

@node Using, Building on Windows, Building on Unix, Top
@chapter Using NetCDF on Unix Systems
@cindex link options
@cindex compiler flags
@cindex nc-config

To use netCDF you must link to the netCDF library, and, if using the
netCDF-4/HDF5 features, also two HDF5, at least one compression
library, and (on some systems) the math library. 

@menu
* Linker Flags::                
* Compiler Flags::              
* nc-config::                   
@end menu

@node Linker Flags, Compiler Flags, Using, Using
@section Using Linker Flags with NetCDF

For this to work, you have to tell the linker which libraries to link
to (with the -l option), and where to find them (with the -L option).

Use the -L option to your linker to pass the directories in which
netCDF, HDF5, and zlib are installed. 

Use the -l (lower-case L) option to list the libraries, which must be
listed in the correct order:

@example
-lnetcdf -lhdf5_hl -lhdf5 -lz -lm
@end example

If szip was used when building HDF5, you must also use -lsz.

On some systems you must also include -lm for the math library.

If HDF4 was used when building netCDF, you must also use -lmfhdf -ldf
-ljpeg.

Finally, if you use the parallel-netcdf library, you must use
-lpnetcdf. 

The worst case scenario is, using all of the above libraries:

@example
-lnetcdf -lpnetcdf -lmfhdf -ldf -ljpeg -lhdf5_hl -lhdf5 -lz -lsz -lm
@end example

In such a case one also needs to provide the locations of the
libraries, with the -L flag. If libraries are installed in the same
directory, this is easier.

Use the nc-config to learn the exact flags needed on your system
(@pxref{nc-config}).

@node Compiler Flags, nc-config, Linker Flags, Using
@section Using Compiler Flags with NetCDF

Depending on how netCDF was built, you may need to use compiler flags
when building your code. For example, many systems build both 32-bit
and 64-bit binaries. The GNU C compiler, for example, uses -m32 and
-m64 as compiler flags for this purpose.

If netCDF is built with the default compiler flags (i.e. no special
flags are used), then no flags need to be used by the user.

If netCDF is built using flags that control architecture or other
important aspects of the binary output, then those flags may need to
be set by all users as well.

@node nc-config,  , Compiler Flags, Using
@section Using the nc-config Utility to Find Compiler and Linker Flags

To assist with the setting of compiler and linker flags, the nc-config
utility is provided with netCDF. The nc-config utility is a very
simple script which contains the settings of the C and Fortran flags
used during the netCDF build. 

For example, the nc-config command can be used to get the command line
options needed to link a C program to netCDF:

@example
nc-config --libs
-L/usr/local/lib -lnetcdf -L/shecky/local_post/lib -lhdf5_hl -lhdf5 -lz
@end example

The nc-config utility can also be used to learn about the features of
the current netCDF installation. For example, it can show whether
netCDF-4 is available:

@example
./nc-config --has-nc4
yes
@end example

Use the --help option to nc-config for a full list of available
information.

@node Building on Windows, Build Problems, Using, Top
@chapter Building and Installing NetCDF on Windows
@cindex windows, building on
@cindex VC++
@cindex NET
@cindex DLL
@cindex Microsoft

NetCDF can be built and used from a variety of development
environments on Windows. The netCDF library is implemented as a
Windows dynamic link library (DLL). The simplest way to get started
with netCDF under Windows is to download the pre-built DLL from the
Unidata web site.

Building under the Cygwin port of GNU tools is treated as a Unix
install. @xref{Platform Notes}.

Instructions are also given for building the netCDF DLL from the
source code.

VC++ documentation being so voluminous, finding the right information
can be a chore. There's a good discussion of using DLLs called ``About
Dynamic-Link Libraries'' at (perhaps)
@uref{http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dllproc/base/dynamic_link_libraries.asp}.

From the .NET point of view, the netCDF dll is unmanaged code. As a
starting point, see the help topic ``Consuming Unmanaged DLL
Functions'' which may be found at
@uref{http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconConsumingUnmanagedDLLFunctions.asp},
unless the page has been moved.

@menu
* Prebuilt DLL::                Getting the Prebuilt DLLs
* Installing DLL::              Installing the DLLs
* Visual Cplusplus::            Building with VC++ 6.0
* Using DLL::                   Using the DLLs with VC++ 6.0
* Building with NET::           Building with VC++ .NET 
* Using with NET::              Using with VC++ .NET
@end menu

@node Prebuilt DLL, Installing DLL, Building on Windows, Building on Windows
@section Getting Prebuilt netcdf.dll
@cindex binaries, windows
@cindex dll, getting

We have pre-built Win32 binary versions of the netcdf dll and static
library, as well as ncgen.exe and ncdump.exe (dll and static
versions). You can get them from
@uref{@value{windows-ftp-site}/netcdf-3.6.1-beta1-win32dll.zip}.
(Note: we don't have a C++ interface here).

@node Installing DLL, Visual Cplusplus, Prebuilt DLL, Building on Windows
@section Installing the DLL
@cindex netcdf.dll, location
@cindex netcdf.lib
@cindex ncgen, windows location
@cindex ncdump, windows location

Whether you get the pre-built DLL or build your own, you'll then have
to install it somewhere so that your other programs can find it and
use it.

To install a DLL, you just have to leave it in some directory, and
(possibly) tell your compiler in which directory to look for it.

A DLL is a library, and functions just like libraries under the Unix
operating system. As with any library, the point of the netCDF DLL is
to provide functions that you can call from your own code. When you
compile that code, the linker needs to be able to find the library,
and then it pulls out the functions that it needs. In the Unix world,
the -L option tells the compiler where to look for a library. In
Windows, library search directories can be added to the project's
property dialog.

Similarly, you will need to put the header file, netcdf.h, somewhere
that you compiler can find it. In the Unix world, the -I option tells
the compiler to look in a certain directory to find header files. In
the Windows world, you set this in the project properties dialog box
of your integrated development environment.

Therefore, installing the library means nothing more than copying the
DLL somewhere that your compiler can find it, and telling the compiler
where to look for them.

The standard place to put DLLs is Windows\System32 folder (for
Windows2000/XP) or the Windows\System folder (for Windows 98/ME). If
you put the DLL there, along with the ncgen and ncdump executables,
you will be able to use the DLL and utilities without further work,
because compilers already look there for DLLs and EXEs.

Instead of putting the DLL and EXEs into the system directory, you can
leave them wherever you want, and every development project that uses
the dll will have to be told to search the netCDF directory when it's
linking, or, the chosen directory can be added to your path.

On the .NET platform, you can also try to use the global assembly
cache. (To learn how, see MSDN topic ``Global Assembly Cache'', at
@uref{www.msdn.microsoft.com}).

Following Windows conventions, the netCDF files belong in the
following places:

@multitable @columnfractions .25 .50 .25

@item File(s) @tab Description @tab Location

@item netcdf.dll @tab C and Fortran function in DLL 
@tab Windows\System (98/ME) or Windows\System32 (2000/XP)

@item netcdf.lib @tab Library file
@tab Windows\System (98/ME) or Windows\System32 (2000/XP)

@item ncgen.exe, ncdump.exe @tab NetCDF utilities
@tab Windows\System (98/ME) or Windows\System32 (2000/XP)

@item netcdf-3 @tab netCDF source code
@tab Program Files\Unidata

@end multitable

@node Visual Cplusplus, Using DLL, Installing DLL, Building on Windows
@section Building netcdf.dll with VC++ 6.0
@cindex VC++ 6.0, building with

The most recent releases of netCDF aren't tested under VC++ 6.0. (They
are tested with VC++.NET). Older versions of the library, notably
3.5.0, did compile with VC++ 6.0, and the instructions for doing so
are presented below.

Note that the introduction of better large file support (for files
larger than 2 GiB) in version 3.6.0 and greater requires an off_t type
of 8 bytes, and it's not clear how, or if, this can be found in VC++
6.0.

To build the library yourself, get the file 
@value{windows-ftp-site}/netcdf-3.5.0.win32make.VC6.zip

The makefiles there describe how to build netcdf-3.5
using the using Microsoft Visual C++ 6.x and (optionally)
Digital Visual Fortran 6.x. Because of difficulties in getting
Microsoft Visual Studio to fall in line with our existing
source directory scheme, we chose _not_ to build the system
"inside" Visual Studio. Instead, we provide a simple group
of "msoft.mak" files which can be used. If you
wish to work in Visual Studio, go ahead. Read the
section called "Macros" at the end of this discussion.

As of this writing, we have not tried compiling the
C++ interface in this environment.

nmake is a Microsoft version of make, which comes with VC 6.0 (and VC
7.0) in directory C:\Program Files\Microsoft Visual Studio\VC98\Bin
(or, for VC 7.0, C:\Program Files\Microsoft Visual Studio .NET
2003\Vc7\bin).

To build netcdf, proceed as follows:

@table @code

@item unpack source distribution.

@item copy netcdf-3.5.0.win32make.VC6.zip 
copy netcdf-3.5.0.win32make.VC6.zip into the netcdf-3.5.0/src
directory, and unzip it from there.

@item cd src\libsrc; nmake /f msoft.mak
Run this command in src\libsrc. This will build netcdf.lib and
netcdf.dll Note: This makefiles make DLLs. To make static libraries
see section on static libraries.

@item nmake /f msoft.mak test
Optionally, in src\libsrc, make and run the simple test.

@item cd ..\fortran; nmake /f msoft.mak
Optionally build the fortran interface and rebuild dll in ..\libsrc to
include the fortran interface. Note Bene: We don't provide a .DEF
file, so this step changes the "ordinals" by which entry points in the
DLL found. Some sites may wish to modify the msoft.mak file(s) to
produce a separate library for the fortran interface.

@item nmake /f msoft.mak test
(necessary if you want to use fortran code) While you are in
src\fortran; nmake /f msoft.mak test This tests the netcdf-2 fortran
interface.

@item cd ..\nctest; nmake /f msoft.mak test
(optional, but recommended) In src\nctest; nmake /f msoft.mak test
This tests the netcdf-2 C interface.

@item cd ..\nc_test; nmake /f msoft.mak test
(optional, but highly recommended) In src\nc_test; nmake /f msoft.mak
test This tortures the netcdf-3 C interface.

@item cd ..\nf_test; nmake /f msoft.mak test
(optional, but highly recommended if you built the fortran interface)
In src\nf_test; nmake /f msoft.mak test This tortures the netcdf-3
fortran interface.

@item ..\ncdump; nmake /f msoft.mak
In src\ncdump; nmake /f msoft.mak This makes ncdump.exe.

@item ..\ncgen; nmake /f msoft.mak
In src\ncgen; nmake /f msoft.mak This makes ncgen.exe.

@item ..\ncdump; nmake /f msoft.mak test
(optional) In src\ncdump; nmake /f msoft.mak test This tests
ncdump. Both ncgen and ncdump need to be built prior to this
test. Note the makefile sets the path so that ..\libsrc\netcdf.dll can
be located.

@item ..\ncgen; nmake /f msoft.mak test
(optional) In src\ncgen; nmake /f msoft.mak test This tests
ncgen. Both ncgen and ncdump need to be built prior to this test. Note
the makefile sets the path so that ..\libsrc\netcdf.dll can be
located.

@item To Install
Copy libsrc\netcdf.lib to a LIBRARY directory.
Copy libsrc\netcdf.h and fortran/netcdf.inc to an INCLUDE directory.
Copy libsrc\netcdf.dll, ncdump/ncdump.exe, and ncgen/ncgen.exe to
a BIN directory (someplace in your PATH).

@end table

@node Using DLL, Building with NET, Visual Cplusplus, Building on Windows
@section Using netcdf.dll with VC++ 6.0
@cindex VC++ 6.0, using netcdf with

To use the netcdf.dll:

1. Place these in your include directory:
	netcdf.h		C include file
	netcdf.inc		Fortran include file

2a. To use the Dynamic Library (shared) version of the netcdf library:
  Place these in a directory that's in your PATH:
	netcdf.dll		library dll
	ncgen.exe		uses the dll
	ncdump.exe		uses the dll

  Place this in a library directory to link against:
	netcdf.lib		library

2b. Alternatively, to use a static version of the library 

  Place this in a library directory to link against:
	netcdfs.lib		library
 
  Place these in a directory that's in your PATH:
	ncgens.exe		statically linked (no DLL needed)
	ncdumps.exe		statically linked (no DLL needed)

@node Building with NET, Using with NET, Using DLL, Building on Windows
@section Building netcdf.dll with VC++.NET
@cindex VC++.NET, building with
@cindex release directory, windows
@cindex debug directory, windows
@cindex testing, for windows
@cindex windows testing
@cindex windows large file tests
@cindex large file tests, for windows
@cindex quick_large_files, in VC++.NET

To build the netCDF dll with VC++.NET open the win32/NET/netcdf.sln
file with Visual Studio. Both Debug and Release configurations are
available - select one and build.

The resulting netcdf.dll file will be in subdirectory Release or
Debug. 

The netCDF tests will be built and run as part of the build
process. The Fortran 77 interface will be built, but not the Fortran
90 or C++ interfaces.

Unfortunately, different fortran compilers require different flag
settings in the netCDF configuration files. (In UNIX builds, this is
handled by the configure script.)

The quick_large_files test program is provided as an extra project,
however it is not run during the build process, but can be run from
the command line or the IDE. Note that, despite its name, it is not
quick. On Unix systems, this program runs in a few seconds, because of
some features of the Unix file system apparently not present in
Windows. Nonetheless, the program does run, and creates (then deletes)
some very large files. (So make sure you have at least 15 GiB of space
available). It takes about 45 minutes to run this program on our
Windows machines, so please be patient.

@node Using with NET,  , Building with NET, Building on Windows
@section Using netcdf.dll with VC++.NET
@cindex VC++.NET, using netcdf with
@cindex visual studio 2003 properties

Load-time linking to the DLL is the most straightforward from
C++. This means the netcdf.lib file has to end up on the compile
command line. This being Windows, that's hidden by a GUI.

In Visual Studio 2003 this can be done by modifying three of the
project's properties. 

Open the project properties window from the project menu. Go to the
linker folder and look at the general properties. Modify the property
``Additional Library Directories'' by adding the directory which
contains the netcdf.dll and netcdf.lib files.  Now go to the linker
input properties and set the property ``Additional Dependencies'' to
netcdf.lib.

Finally, still within the project properties window, go to the C/C++
folder, and look at the general properties. Modify ``Additional
Include Directories'' to add the directory with the netcdf.h file.

Now use the netCDF functions in your C++ code. Of course any C or C++
file that wants to use the functions will need:

@example
#include <netcdf.h>
@end example

@node Build Problems, Combined Index, Building on Windows, Top
@chapter If Something Goes Wrong

The netCDF package is designed to build and install on a wide variety
of platforms, but doesn't always. It's a crazy old world out there,
after all.

@menu
* Usual Problems::              Problems which Occur Often
* Troubleshooting::             Finding the Problem
* Finding Help::                Getting Support
* Reporting Problems::          What to Send to Support
@end menu

@node Usual Problems, Troubleshooting, Build Problems, Build Problems
@section The Usual Build Problems

@subsection Taking the Easy Way Out

Why not take the easy way out if you can? 

Many Linux systems contain package management programs which allow
netCDF to be installed easily. This is the prefered installation
method for netCDF.

Precompiled binaries for some platforms can be found at
@url{@value{netcdf-binaries-url}}. Click on your platform, and copy
the files from the bin, include, lib, and man directories into your
own local equivalents (Perhaps /usr/local/bin, /usr/local/include,
etc.).

@subsection How to Clean Up the Mess from a Failed Build

If you are trying to get the configure or build to work, make sure you
start with a clean distribution for each attempt. If netCDF failed in
the ``make'' you must clean up the mess before trying again. To clean
up the distribution:

@example
make distclean
@end example

@subsection Platforms On Which NetCDF is Known to Work

At NetCDF World Headquarters (in sunny Boulder, Colorado), as part of
the wonderful Unidata organization, we have a wide variety of
computers, operating systems, and compilers. At night, house elves
test netCDF on all these systems. 

Output for the netCDF test platforms can be found at
@url{@value{netcdf-builds}}.

Compare the output of your build attempt with ours. Are you using the
same compiler? The same flags? Look for the configure output that
lists the settings of CC, FC, CXX, CFLAGS, etc. 

On some systems you have to set environment variables to get the
configure and build to work. 

For example, for a 64-bit IRIX install of the netCDF-3.6.2 release,
the variables are set before netCDF is configured or built. In this
case we set CFLAGS, CXXFLAGS, FCFLAGS, and FFLAGS. 

@example
flip% uname -a
IRIX64 flip 6.5 07080050 IP30 mips
flip% setenv CFLAGS -64
flip% setenv CXXFLAGS -64
flip% setenv FFLAGS -64
flip% setenv FCFLAGS -64
flip% make distclean;./configure;make check
@end example

@subsection Platforms On Which NetCDF is Reported to Work

If your platform isn't listed on the successful build page, see if
another friendly netCDF user has sent in values for environment
variables that are reported to work:
(@uref{@value{netcdf-other-builds}}).

If you build on a system that we don't have at Unidata (particularly
if it's something interesting and exotic), please send us the settings
that work (and the entire build output would be nice too). Send them
to @value{netcdf-support-email}.

@subsection If You Have a Broken Compiler

For netCDF to build correctly, you must be able to compile C from your
environment, and, optionally, Fortran 77, Fortran 90, and C++. If
C doesn't work, netCDF can't compile. 

What breaks a C compiler? Installation or upgrade mistakes when the C
compiler was installed, or multiple versions or compilers installed on
top of each other. Commercial compilers frequently require some
environment variables to be set, and some directories to appear ahead
of others in your path. Finally, if you have an expired or broken
license, your C compiler won't work.

If you have a broken C compiler and a working C compiler in your PATH,
netCDF might only find the broken one. You can fix this by explicitly
setting the CC environmental variable to a working C compiler, and
then trying to build netCDF again. (Don't forget to do a ``make
distclean'' first!)

If you can't build a C program, you can't build netCDF. Sorry, but
that's just the way it goes. (You can get the GNU C compiler - search
the web for ``gcc'').

If netCDF finds a broken Fortran 90, Fortran 77, or C++ compiler, it
will report the problem during the configure, and then drop the
associated API. For example, if the C++ compiler can't compile a very
simple test program, it will drop the C++ interface. If you really
want the C++ API, set the CXX environment variable to a working C++
compiler.

@subsection What to Do If NetCDF Still Won't Build

If none of the above help, try our troubleshooting section:
@xref{Troubleshooting}.

Also check to see of your problem has already been solved by someone
else (@pxref{Finding Help}).

If you still can't get netCDF to build, report your problem to
Unidata, but please make sure you submit all the information we need
to help (@pxref{Reporting Problems}).

@node Troubleshooting, Finding Help, Usual Problems, Build Problems
@section Troubleshooting
@cindex troubleshooting
@cindex turning off C++, Fortran interface

@subsection Problems During Configuration

If the ./configure; make check fails, it's a good idea to turn off the
C++ and Fortran interfaces, and try to build the C interface
alone. All other interfaces depend on the C interface, so nothing else
will work until the C interface works. To turn off C++ and Fortran,
set environment variables CXX and FC to NULL before running the netCDF
configure script (with csh: setenv FC '';setenv CXX '').

Turning off the Fortran and C++ interfaces results in a much shorter
build and test cycle, which is useful for debugging problems.

If the netCDF configure fails, most likely the problem is with your
development environment. The configure script looks through your path to
find all the tools it needs to build netCDF, including C compiler and
linker, the ar, ranlib, and others. The configure script will tell
you what tools it found, and where they are on your system. Here's
part of configure's output on a Linux machine:

@example
checking CPPFLAGS...  -Df2cFortran
checking CC CFLAGS... cc -g
checking which cc... /usr/bin/cc
checking CXX... c++
checking CXXFLAGS... -g -O2
checking which c++... /usr/local/bin/c++
checking FC... f77
checking FFLAGS... 
checking which f77... /usr/bin/f77
checking F90... unset
checking AR... ar
checking ARFLAGS... cru
checking which ar... /usr/bin/ar
checking NM... nm
checking NMFLAGS... 
checking which nm... /usr/bin/nm
@end example

Make sure that the tools, directories, and flags are set to reasonable
values, and compatible tools. For example the GNU tools may not
inter-operate well with vendor tools. If you're using a vendor
compiler, you may need to use the ar, nm, and ranlib that the vendor
supplied.

As configure runs, it creates a config.log file. If configure crashes,
do a text search of config.log for thing it was checking before
crashing. If you have a licensing or tool compatibility problem, it
will be obvious in config.log.

@subsection Problems During Compilation

If the configure script runs, but the compile step doesn't work, or
the tests don't complete successfully, the problem is probably in your
CFLAGS or CPPFLAGS. 

Frequently shared libraries are a rich source of problems. If your
build is not working, and you are using the --enable-shared option to
generate shared libraries, then try to build without --enable-shared,
and see if the static library build works.

@subsection Problems During Testing

If you are planning on using large files (i.e. > 2 GiB), then you may
wish to rerun configure with --enable-large-file-tests to ensure that
large files work on your system.

Some DAP tests (in the directory ncdap_test) attempt to access an
external server at opendap.org.  It is possible that the DAP server
may not be running at test time, or the network access may be
faulty or that the output of the test server has changed.
In this case, the DAP tests may fail. Because of this,
the use of these tests is controlled by the --enable-dap-remote-tests
option.

@node Finding Help, Reporting Problems, Troubleshooting, Build Problems
@section Finding Help On-line
@cindex mailing lists
@cindex documentation
@cindex FAQ for netCDF
@cindex other builds document
@cindex successful build output, on web
@cindex known problems

The latest netCDF documentation (including this manual) can be found
at @uref{@value{docs-url}}.

The output of successful build and test runs for recent versions of
netCDF can be found at @uref{@value{netcdf-builds}}.

A list of known problems with netCDF builds, and suggested fixes, can
be found at @uref{@value{known-problems-url}}.

Reportedly successful settings for platforms unavailable for netCDF
testing can be found at @uref{@value{netcdf-other-builds}}. If you
build netCDF on a system that is not listed, please send your
environment settings, and the full output of your configure, compile,
and testing, to @value{netcdf-support-email}. We will add the
information to the other-builds page, with a credit to you.

The replies to all netCDF support emails are on-line and can be
searched. Before reporting a problem to Unidata, please search this
on-line database to see if your problem has already been addressed in
a support email. If you are having build problems it's usually useful
to search on your system host name. On Unix systems, use the uname
command to find it.

The netCDF Frequently Asked Questions (FAQ) list can be found at
@uref{@value{netcdf-faq-url}}.

To search the support database, see @uref{@value{netcdf-support-search-url}}.

The netCDF mailing list also can be searched; see
@uref{@value{netcdf-list-search-url}}.

@node Reporting Problems,  , Finding Help, Build Problems
@section Reporting Problems
@cindex bugs, reporting
@cindex problems, reporting
@cindex reporting problems
@cindex support email

To help us solve your problem, please include the following
information in your email to @uref{@value{netcdf-support-email}}. 

Unfortunately, we can't solve build questions without this
information; if you ask for help without providing it, we're just
going to have to ask for it.

So why not send it immediately, and save us both the extra trouble?

@enumerate

@item the exact version of netCDF - see the VERSION file.

@item the *complete* output of ``./configure'', ``make'', and ``make check. Yes,
it's long, but it's all important.

@item if the configure failed, the contents of config.log.

@item if you are having problems with very large files (larger than
2GiB), send the output of "make check" after first running "make
distclean" and invoking the configure script with the
--enable-large-file-tests option included.

@end enumerate

Although responses to your email will be available in our support
database, your email address is not included, to provide spammers with
one less place to harvest it from.

@node Combined Index,  , Build Problems, Top
@unnumbered Index

@printindex cp

@bye
End:
