Compiling program using gfortran and the HDF-EOS2 library

Question

I have the problem of linking the HDF-EOS library to a Fortran90 program. I have compiled the library from source to a directory specified in $prefix. My simple compile command is:

gfortran -I$prefix/include -L$prefix/lib -Wl,-rpath -Wl,$prefix/lib -lhdfeos -lGctp -lmfhdf -ldf -lz -lsz -ljpeg tst.f90

When compiling, I get the following error:

undefined reference to `gdopen_'

In the program, which I am not supposed to change, the HDF-EOS library is used via the external keyword, e.g.

integer(kind=4), external :: gdopen

In the library, nm $prefix/lib/libhdfeos.a | grep gdopen gives me:

00000000000120c0 T gdopen

When compiling with -fno-underscoring, I get just a different error:

gfortran -fno-underscoring -I$prefix/include -L$prefix/lib -Wl,-rpath -Wl,$prefix/lib -lhdfeos -lGctp -lmfhdf -ldf -lz -lsz -ljpeg tst.f90

the error is then:

undefined reference to `gdopen'

Also, gfortran finds the libraries, otherwise it would complain. Is the error related to the underscore? What else can I try? I work on Fedora and gfortran version 4.7.2.

Vladimir F Героям слава · Answer 1 · 2014-10-22T15:09:03.870

1

Yes, very likely to be caused by the underscore.

Try compiling with -fno-underscoring (https://gcc.gnu.org/onlinedocs/gfortran/Code-Gen-Options.html), but fixing it by a proper bind(C) interface would be better.

This tutorial (Did you read it before going here? Very easy to find even for a complete novice in the library, like me.) also states you should use -fno-underscoring.

Continue by implementing the rest what the tutorial recommends, including compiling with FC=$(HDF4_DIR)/bin/h4fc.

edited Oct 22 '14 at 15:09

answered Oct 22 '14 at 14:52

Vladimir F Героям слава

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I should have mentioned that in the question, I tried it, but with no success, I will update my question accordingly. – Andre Oct 22 '14 at 15:03
@Andre BTW, "gfortran finds the libraries, otherwise it would complain" is completely false. – Vladimir F Героям слава Oct 22 '14 at 15:07
Yes I did, it didn't help me, then I moved on and eventually came here. Shouldn't gfortran complain if I use -lhdfeos and it is not able to find a libhdfeos.a file? – Andre Oct 22 '14 at 15:11
The linker should complain, but that is after the compilation by gfortran is finished. But you do not specify `libhdfeos.a` in your example, it could also be using a dynamic library. – Vladimir F Героям слава Oct 22 '14 at 15:13
Ok, I thought I was doing that by adding the -lhdfeos parameter. – Andre Oct 22 '14 at 15:17
Yes, you were, but it could also link a dynamic version of the library, if it exists. It shouldn't change much though. – Vladimir F Героям слава Oct 22 '14 at 15:19
I was using this FC=$(HDF4_DIR)/bin/h4fc example to come up with the gfortran command line, it is a tool that basically gives you a proper gfortran command. – Andre Oct 22 '14 at 15:20
Rgr., it would help next time to describe more thoroughly in the question what you have tried. – Vladimir F Героям слава Oct 22 '14 at 15:32

Compiling program using gfortran and the HDF-EOS2 library

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