[netCDF #NBS-392373]: libnetcdf.so should be linked with -lhdf5_hl -lhdf5 when --enable-netcdf-4

Jed- I have modified the
netcdf-c documentation to try to
elaborate on the linking issue.
I have included it below.
Comments welcome.

=Dennis Heimbigner

...Every C file that references netCDF functions or constants must
contain an appropriate #include statement before the first such
reference:

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

Unless the netcdf.h file is installed in a standard directory where
the C compiler always looks, you must use the -I option when invoking
the compiler, to specify a directory where netcdf.h is installed, for
example:

@example
cc -c -I/usr/local/netcdf/include myprogram.c
@end example

Alternatively, you could specify an absolute path name in the #include
statement, but then your program would not compile on another platform
where netCDF is installed in a different location.

Unless the netCDF library is installed in a standard directory where
the linker always looks, you must use the -L and -l options to link an
object file that uses the netCDF library.

If the netCDF library was configured with the --enable-shared
flag, and the operating system supports shared libraries, then it
should be possible to link an application program using a relatively
simple command. For example:

@example
cc -o myprogram myprogram.o -L/usr/local/netcdf/lib -lnetcdf
@end example

It should be noted that on many operating systems, when using
shared libraries, the application itself must be compiled
using the -fPIC or -PIC flag (depending on the C compiler).

In addition, for some operating systems (e.g. Solaris),
it is necessary to specify runtime paths to the relevant libnetcdf.so.
This can be accomplished in one of two ways.
@enumerate
@item
Add the path to the directory containing libnetcdf.so
to the LD_LIBRARY_PATH environment variable.
This path is searched at runtime to locate any needed shared library.
This might be accomplished, for example, by the following shell command
(assuming that libnetcdf.so is in /usr/local/netcdf/lib).
@example
LD_LIBRARY_PATH="/usr/local/netcdf/lib:$LD_LIBRARY_PATH"
export LD_LIBRARY_PATH
@end example

@item
Set the so-called runtime path when the application is linked
so that the absolute paths of all needed shared libraries is
included in the application binary.
For Linux, this is usually automatic. For Solaris (and probably
other operating systems) the runtime path must be specified at
link time. The Solaris command would look like this.
@example
cc -o myprogram myprogram.o -L/usr/local/netcdf/lib -lnetcdf 
-R/usr/local/netcdf/lib
@end example
@end enumerate

If shared libraries are not supported or are not being used for some
reason, then it is necessary to include all the dependent libraries in
the compile command.  For example, for a netCDF-4 enabled library, it
will be necessary to link with two HDF5 libraries,
at least one compression library, and
(on some systems) the math library:

@example
cc -o myprogram myprogram.o -L/usr/local/netcdf/lib -L/usr/local/hdf5/lib 
-lnetcdf -lhdf5_hl -lhdf5 -lz
@end example

A complete list of necessary libraries can be obtained by
executing the ``nc-config --libs'' command.
For example:
@example
./nc-config --libs
@end example
might return something like this:
@example
-L/tmp/install/spock/lib -lnetcdf -L/upc/share/stdinstall/local/spock/lib
-lhdf5_hl -lhdf5 -L/upc/share/stdinstall/local/spock/lib -lz -lm
-L/upc/share/stdinstall/local/spock/lib -lcurl -L/usr/kerberos/lib64
-L/upc/share/stdinstall/local/spock/lib
-lidn -lssl -lcrypto -lldap -lrt -lssl -lcrypto -ldl -lz -lz
@end example

Obviously there is some redundancy in this list, so it can be reduced
somewhat to produce this slightly simpler list.
@example
-L/tmp/install/spock/lib -lnetcdf
-L/upc/share/stdinstall/local/spock/lib -lhdf5 -lhdf5_hl -lz -lcurl
-L/usr/kerberos/lib64 -lcrypto -lssl
-ldl -lidn -lldap -lm -lrt
@end example





Ticket Details
===================
Ticket ID: NBS-392373
Department: Support netCDF
Priority: High
Status: Open