NetCDF Installation and Porting Guide

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NetCDF Installation and Porting Guide

This document describes how to build and install the netCDF library, version 3.6.0 and later, on Unix and Windows systems. Instructions for installing earlier versions of netCDF can be found at http://www.unidata.ucar.edu/software/netcdf/INSTALL_pre_360.html.

For a complete description of the netCDF format and utilities see The NetCDF Users' Guide.

Programming guides are available for C (see Top), C++ (see Top), Fortran 77 (see Top), and Fortran 90 (see Top). All of these documents are available from the netCDF website http://www.unidata.ucar.edu/packages/netcdf/.

Separate documentation for the netCDF Java library can be found at the netCDF-Java website, http://www.unidata.ucar.edu/software/netcdf-java/index.html.

To learn more about netCDF, see the netCDF website http://www.unidata.ucar.edu/packages/netcdf/.

--- The Detailed Node Listing ---

Building and Installing NetCDF on Unix Systems

Building and Installing NetCDF on Windows

If Something Goes Wrong

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1 Quick Instructions for Installing NetCDF on Unix

Who has time to read long installation manuals these days?

To install netCDF, uncompress and unpack the tar file, then change to the src directory: 

     gunzip netcdf-3_6_0.tar.gz
     tar -xf netcdf-3_6_0.tar
     cd netcdf-3_6_0/src

Now run the usual configure, make test, make install cycle: 

     ./configure
     make test
     make install

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, the following will install the library in /usr/local/lib, the header file in /usr/local/include, and the utilities in /usr/local/bin. 

     ./configure --prefix=/usr/local

The default install root is .. (i.e. the parent directory, which will be netcdf-3_6_0).

If all this doesn't work, then you might have to read the next chapter. Better luck next time!

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2 Building and Installing NetCDF on Unix Systems

The latest version of this document is available at http://www.unidata.ucar.edu/packages/netcdf/INSTALL_beta/index.html.

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 http://www.unidata.ucar.edu/packages/netcdf/binaries.html.

This document describes installation of version 3.6.0 (beta) of the netCDF library, for information about installing earlier versions of netCDF, see http://www.unidata.ucar.edu/packages/netcdf/INSTALL.html.

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2.1 Installation Requirements

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.

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 as part of the make test step; they are only run for make extra_test.

If you wish to build from source on a Windows (Win32) platform, different instructions apply. See Building and Installing NetCDF on Windows.

To fully 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 tools. All are freeware.

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 and 3.6.0.
nm
Lists contents of an “object” file. GNU nm does not mix well with vendor compilers in the 64-bit world, so make sure that you are using GNU nm with GNU compilers, or a vendor nm with your vendor compiler.
ar
Creates libraries. GNU ar does not mix well with vendor compilers in the 64-bit world, so make sure that you are using GNU ar with GNU compilers, or a vendor ar with your vendor compiler.

The following tools are not required to build netCDF. They may be needed if you intend to work with the netCDF source code as a developer.

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.
makeinfo
Generates all documentation formats (except man pages) from texinfo source. I'm using makeinfo version 4.2, as of release 3.6.0. If you have trouble with makeinfo, upgrade to at least 4.2 and try again. You only need makeinfo if you want to modify the documentation.
autoconf
Generates the configure script. Autoconf is only needed to modify the configure script. Version 2.59 or later is required. Automake is not used with netCDF version 3.6.

The most recent version of all netCDF documents can always be found at the netCDF website. http://www.unidata.ucar.edu/packages/netcdf/.

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2.2 Specifying the Environment for Building

The netCDF configure script will set some environment variables that are important for building from source code. It is only necessary to set them to override default behavior.

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.

When finding compilers, vendor compilers will be preferred to GNU compilers. Not because we don't like GNU, but because we assume if you purchased a compiler, you want to use it. Setting CC allows you to over-ride this preference. (Alternatively, you could temporarily remove the compiler's directories from your PATH.)

For example, on an AIX system, configure will first search for xlc, the AIX compiler. If not found, it will try gcc, the GNU compiler. To override this behavior, set CC to gcc (in sh: export CC=gcc). (But don't forget to also set CXX to g++, or else configure will try and use xlC, the AIX C++ compiler.)

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).

Variable Description Notes

CC C compiler If you don't specify this, the configure script will try to find a suitable C compiler such as cc, c89, xlc, or gcc.


FC Fortran compiler (if any) If you don't specify this, the configure script will try to find a suitable Fortran 90 or Fortran 77 compiler. Set FC to "" explicitly, if no Fortran interface is desired.


F90 Fortran 90 compiler (if any) If you don't specify this, the configure script will try to find a suitable Fortran 90 compiler. Not needed if FC specifies a Fortran 90 compiler. Set F90 to "" explicitly, if no Fortran 90 interface desired. For a vendor F90 compiler, make sure you're using the same vendor's F77 compiler. Using Fortran compilers from different vendors, or mixing vendor compilers with g77, the GNU F77 compiler, is not supported and may not work.


CXX C++ compiler If you don't specify this, the configure script will try to find a suitable C++ compiler. Set CXX to "" explicitly, 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.


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


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


FFLAGS Fortran compiler flags "-O" or "-g", for example.


F90FLAGS Fortran 90 compiler flags "-O" or "-g", for example. If you don't specify this, the value of FFLAGS will be used.


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


ARFLAGS, NMFLAGS, FPP, M4FLAGS, LIBS, FLIBS, FLDFLAGS Miscellaneous 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.

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.

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2.3 Building on 64 Bit Platforms

Some platforms support special options to build in 64-bit mode.

NetCDF 3.6.0 beta has been tested as 64-bit builds on SunOS and AIX. The options needed to build in 64-bit mode are described here.

AIX
Set -q64 option in all compilers, and set NMFLAGS to -X32, and ARFLAGS to '-X32 cru'. Alternatively, set environment variable OBJECT_MODE to 64 before running configure.
IRIX
Set the -64 option in all compilers.
SunOS
Use the -xarch=v9 flag on all compilers. This is not supported on the x86 platform.

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2.4 Running the configure Script

To create the Makefiles needed to build netCDF, you must run the provided configure script. Go to the top-level netCDF src/ 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 "..", which will install the package's files in ../bin, ../lib, and ../man relative to the netCDF src/ directory.

Execute the configure script: 

         ./configure --prefix=whatever_you_decided

The "–prefix=..." specification is optional; if omitted, ".." designating the parent directory will be used as a default.

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.

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2.5 Running make

Run "make". This will build one or more netCDF libraries. It will build the basic netCDF library libsrc/libnetcdf.a. If you have Fortran 77 or Fortran 90 compilers, then the Fortran interfaces will be included in this library. If you have a C++ compiler, then the C++ interface will be built into the library cxx/libnetcdf_c++.a. This will also build the netCDF utilities ncgen(1) and ncdump(1).

Run make like this: 

     make

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2.6 Testing the Build

Run "make test" to verify that the netCDF library and executables have been built properly. This 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: 

     make test

If you plan to use the 64-bit offset format (introduced in version 3.6.0) to create very large files (i.e. larger than 2 GB), you should probably run “make extra_test” which tests the large file features. You must have 13 GB of free disk space for these tests to successfully run. (The test files are deleted when the test completes, so you get your disk space back.) You may wish to et environment variable TEMP_LARGE to a directory to which large files can be written. (For example, in csh: setenv TEMP_LARGE /ptmp/edh).

Run the large file tests like this: 

     make extra_test

If the tests fail See If Something Goes Wrong.

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2.7 Installing NetCDF

To install the libraries and executables, run "make install". This will install to the directory specified in the configure step, or to ../lib (that is, it will create a lib directory under the netcdf-3.6.0 directory, and install the library there.)

Run the installation like this: 

     make install

Try linking your applications. Let us know if you have problems (see Reporting Problems). Port the library to other platforms. Share data.

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2.8 Platform Specific Notes

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 3.6.0 can be found at http://www.unidata.ucar.edu/packages/netcdf/builds/.

2.8.1 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 (we hope): 

         F90FLAGS=-qsuffix=f=f90

To compile 64-bit code, set the environment variable OBJECT_MODE 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: 

         ARFLAGS='-X64 cru'
         NMFLAGS='-X64'

There are thread-safe versions of the AIX compilers. For example, xlc_r is the thread-safe C compiler. The NetCDF configure script ignores these compilers. 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.

2.8.2 Cygwin

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

2.8.3 HPUX

The HP Fortran compiler (f77, a.k.a. fort77) 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: 

         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

2.8.4 Irix

A 64-bit version can be built 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.

2.8.5 Linux

The f2cFortran flag is required with GNU fortran: 

         CPPFLAGS=-Df2cFortran

For Portland Group Fortran, set pgiFortran instead: 

         CPPFLAGS=-DpgiFortran

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.

2.8.6 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): 

         CC=/usr/bin/cc
         CPPFLAGS=-DIBMR2Fortran
         FC=xlf
         F90=xlf90
         F90FLAGS=-qsuffix=cpp=f90

2.8.7 OSF1

NetCDF builds out of the box on OSF1.

2.8.8 SunOS

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

For large file support, _FILE_OFFSET_BITS must be 64. Configure will turn this on automatically.

Large file support doesn't work with c89, unless the -Xa option is used. The netCDF configure script turns this on automatically where appropriate.

To compile in 64-bit mode, use option -xarch=v9 on all compilers (i.e. in CFLAGS, FFLAGS, 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.

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2.9 Additional Porting Notes

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.

If you can't run the configure script, you will need to create libsrc/ncconfig.h and fortran/nfconfig.inc. Start with libsrc/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.

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.

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3 Building and Installing NetCDF on Windows

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.

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) 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 http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/html/cpconConsumingUnmanagedDLLFunctions.asp.

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3.1 Getting Prebuilt netcdf.dll

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 ftp://ftp.unidata.ucar.edu/pub/netcdf/contrib/win32/netcdf-3.5.0.win32bin.zip. (Note: we don't have a C++ interface here).

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3.2 Installing the DLL

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.

There are standard places to put DLLs, the Windows\System folder (Windows 98/ME) or Windows\System32 folder (Windows2000/XP), or 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.

On the .NET platform, there is also the global assembly cache (see MSDN topic “Global Assembly Cache”).

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

File(s) Description Location


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


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


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


netcdf-3\src netCDF source code Program Files\Unidata

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3.3 Building netcdf.dll with VC++ 6.0

To build the library yourself, get the file ftp://ftp.unidata.ucar.edu/pub/netcdf/contrib/win32/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:

unpack source distribution.
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.
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.
nmake /f msoft.mak test
Optionally, in src\libsrc, make and run the simple test.
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.
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.
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.
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.
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.
..\ncdump; nmake /f msoft.mak
In src\ncdump; nmake /f msoft.mak This makes ncdump.exe.
..\ncgen; nmake /f msoft.mak
In src\ncgen; nmake /f msoft.mak This makes ncgen.exe.
..\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.
..\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.
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).

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3.4 Using netcdf.dll with VC++ 6.0

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)

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3.5 Building netcdf.dll with 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.

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3.6 Using netcdf.dll with VC++.NET

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's 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: 

     #include <netcdf.h>

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4 If Something Goes Wrong

The netCDF package is designed to build and install on a wide variety of platforms, but doesn't always. When the automatic install doesn't work, first see if the problem is something obvious (see Troubleshooting). If that doesn't help, try seeing if your problem has already been solved by someone else (see Finding Help). If that doesn't help, report your problem to Unidata, but please make sure you submit all the information we need to help (see Reporting Problems).

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4.1 Troubleshooting

If the ./configure;make test 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 ”).

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 your what tools it's found, and where they are on your system. Here's part of configure's output on a Linux machine: 

     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
     checking RANLIB... ranlib
     checking RANLIBFLAGS...
     checking which ranlib... /usr/bin/ranlib

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, 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.

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.

If you are planning on using large files (i.e. > 2 GiB), then make sure you run make extra_test to ensure that large files work on your system.

Next: , Previous: Troubleshooting, Up: If Something Goes Wrong

4.2 Finding Help On-line

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.

To search the support database, see netcdf-support-search-url.

The netCDF mailing list also can be searched; see netcdf-list-search-url.

Previous: Finding Help, Up: If Something Goes Wrong

4.3 Reporting Problems

To help us solve your problem, please include the following information in your email to support@unidata.ucar.edu.

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?

  1. the exact version of netCDF - see the src/VERSION file.
  2. the *complete* output of ./configure, make, and make test. Yes, it's long, but it's all important.
  3. if the configure failed, the contents of config.log.
  4. if you are having problems with very large files (larger than 2GiB), the output of make extra_test.

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