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This page describes an example of how to call liboctave functions from a Fortran program. | This page describes an example of how to call liboctave functions from a Fortran program. | ||
In the example we will load | In the example we will load a single matrix, stored in ASCII format, from a data file. | ||
It consists of two steps: | |||
# write a C++ function with a C compatible interface and C linkage that reads a variable from an Octave ASCII file | |||
# write Fortran code using the "iso_c_binding" intrinsic module to call the C++ function | |||
=== Data file === | |||
{{File|data.txt|<syntaxhighlight lang="text"> | |||
1.59797350e-01 5.41307474e-01 1.12127655e-01 2.09249248e-01 | |||
3.22564589e-01 7.94307947e-01 8.25924316e-01 5.38352076e-01 | |||
3.63990736e-01 1.90371212e-02 2.89370865e-01 1.30131246e-01 | |||
6.28360462e-01 1.98831330e-01 6.89539723e-01 6.91062597e-01 | |||
</syntaxhighlight>}} | |||
The file was generated with | |||
<syntaxhighlight lang="octave"> | |||
A = rand (4); | |||
save -ascii data.txt A | |||
</syntaxhighlight> | |||
=== C++ function === | === C++ function === | ||
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#endif | #endif | ||
int octave_load (const char* filename | int octave_load (const char* filename, double** data, int* numel); | ||
#ifdef __cplusplus | #ifdef __cplusplus | ||
| Line 115: | Line 131: | ||
=== Compiling the code === | === Compiling the code === | ||
Generate {{Path|octave_file_io.o}} from {{Path|octave_file_io.cc}}. | |||
mkoctfile -I. -c octave_file_io.cc | |||
Generate {{Path|octave_file_io_example.exe}} from {{Path|octave_file_io_example.f90}} including {{Path|octave_file_io.o}}. | |||
mkoctfile -I. --link-stand-alone octave_file_io_example.f90 octave_file_io.o -o octave_file_io_example.exe -lgfortran | |||
If you receive errors about missing libraries, make sure your <code>LD_LIBRARY_PATH</code> is set correctly to find all Octave libraries, e.g. | |||
$ ldd ./octave_file_io_example.exe | |||
... | |||
libgfortran.so.4 => /usr/lib64/libgfortran.so.4 (0x00007fe9eb62b000) | |||
liboctinterp.so.8 => not found | |||
liboctave.so.8 => not found | |||
... | |||
Then find {{Path|liboctinterp.so.8}} and {{Path|liboctave.so.8}} on your system and type | |||
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/path/to/lib/octave/{{Release}}/ | |||
[[Category:Examples]] | [[Category:Examples]] | ||