P3DFFT compilation - "Undefined reference" but libraries are linked - compilation

Question

I need help with compilation of P3DFFT. I'm literally lost in the process, because the compiler is complaining about "undefined reference" to lots of symbols, but those symbols are present in the libraries.
My command:
mpicc -g -O2 -I../../include -L/home/martin/fftw3/libs -lfftw3 /home/martin/p3dfft/build/libp3dfft.a driver_rand.c -o driver_rand
Compiler output:
driver_rand.c: In function ‘main’:
driver_rand.c:114:10: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result]
fscanf(fp,"%d %d %d %d %d\n",&nx,&ny,&nz,&ndim,&n);
^
driver_rand.c:137:8: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result]
fscanf(fp,"%d %d\n",dims,dims+1);
^
/tmp/cc52N8Sc.o: In function `Cp3dfft_setup':
/home/martin/p3dfft/sample/C/../../include/p3dfft.h:90: undefined reference to `p3dfft_setup'
/tmp/cc52N8Sc.o: In function `Cp3dfft_get_dims':
/home/martin/p3dfft/sample/C/../../include/p3dfft.h:100: undefined reference to `p3dfft_get_dims'
/home/martin/p3dfft/sample/C/../../include/p3dfft.h:100: undefined reference to `p3dfft_get_dims'
/tmp/cc52N8Sc.o: In function `Cp3dfft_clean':
/home/martin/p3dfft/sample/C/../../include/p3dfft.h:95: undefined reference to `p3dfft_clean'
/tmp/cc52N8Sc.o: In function `Cget_timers':
/home/martin/p3dfft/sample/C/../../include/p3dfft.h:105: undefined reference to `get_timers'
/tmp/cc52N8Sc.o: In function `Cset_timers':
/home/martin/p3dfft/sample/C/../../include/p3dfft.h:110: undefined reference to `set_timers'
/tmp/cc52N8Sc.o: In function `Cp3dfft_ftran_r2c':
/home/martin/p3dfft/sample/C/../../include/p3dfft.h:117: undefined reference to `p3dfft_ftran_r2c'
/tmp/cc52N8Sc.o: In function `Cp3dfft_btran_c2r':
/home/martin/p3dfft/sample/C/../../include/p3dfft.h:130: undefined reference to `p3dfft_btran_c2r'
/tmp/cc52N8Sc.o: In function `main':
/home/martin/p3dfft/sample/C/driver_rand.c:106: undefined reference to `set_timers'
/tmp/cc52N8Sc.o: In function `Cp3dfft_setup':
/home/martin/p3dfft/sample/C/../../include/p3dfft.h:90: undefined reference to `p3dfft_setup'
/tmp/cc52N8Sc.o: In function `Cp3dfft_get_dims':
/home/martin/p3dfft/sample/C/../../include/p3dfft.h:100: undefined reference to `p3dfft_get_dims'
/home/martin/p3dfft/sample/C/../../include/p3dfft.h:100: undefined reference to `p3dfft_get_dims'
/tmp/cc52N8Sc.o: In function `Cp3dfft_ftran_r2c':
/home/martin/p3dfft/sample/C/../../include/p3dfft.h:117: undefined reference to `p3dfft_ftran_r2c'
/tmp/cc52N8Sc.o: In function `Cp3dfft_btran_c2r':
/home/martin/p3dfft/sample/C/../../include/p3dfft.h:130: undefined reference to `p3dfft_btran_c2r'
/tmp/cc52N8Sc.o: In function `Cp3dfft_clean':
/home/martin/p3dfft/sample/C/../../include/p3dfft.h:95: undefined reference to `p3dfft_clean'
/tmp/cc52N8Sc.o: In function `main':
/home/martin/p3dfft/sample/C/driver_rand.c:258: undefined reference to `get_timers'
collect2: error: ld returned 1 exit status
Undefined symbols ARE present in libp3dfft.a:
nm ../../build/libp3dfft.a --defined-only | grep 'p3dfft_setup'
000000000000d030 T __p3dfft_MOD_p3dfft_setup
0000000000010ed0 T p3dfft_setup
nm ../../build/libp3dfft.a --defined-only | grep 'get_timers'
00000000000052f0 T get_timers
0000000000005230 T __p3dfft_MOD_get_timers
Do you have ANY idea what am I doing wrong?

Answer 1

I'm not familiar with your particular compiler, but I think you may need to correct the order of the source file and the libraries on your command line, i.e.
mpicc -g -O2 -I../../include -L/home/martin/fftw3/libs -lfftw3 /home/martin/p3dfft/build/libp3dfft.a driver_rand.c -o driver_rand
should probably be:
mpicc -g -O2 -I../../include driver_rand.c /home/martin/p3dfft/build/libp3dfft.a -L/home/martin/fftw3/libs -lfftw3 -o driver_rand