Cplex library gcc compilation link error

问题:

gcc -I/opt/cplex-studio-125/cplex/include -lcplex -L/opt/cplex-studio-125/cplex/lib/x86-64_sles10_4.1/static_pic mipex1.c 

I'm trying to compile an example from cplex. -I option is fine. The -L option seems to be corrupt, since it can't find the function names.

Where is the error? In the specifiec link there is a libcplex.a.

/tmp/ccf5sKky.o: In function `main':
mipex1.c:(.text+0x9f): undefined reference to `CPXopenCPLEX'
mipex1.c:(.text+0xee): undefined reference to `CPXgeterrorstring'
mipex1.c:(.text+0x125): undefined reference to `CPXsetintparam'
mipex1.c:(.text+0x222): undefined reference to `CPXcreateprob'
mipex1.c:(.text+0x2e1): undefined reference to `CPXcopylp'
mipex1.c:(.text+0x334): undefined reference to `CPXcopyctype'
mipex1.c:(.text+0x380): undefined reference to `CPXmipopt'
mipex1.c:(.text+0x3cc): undefined reference to `CPXgetstat'
mipex1.c:(.text+0x403): undefined reference to `CPXgetobjval'
mipex1.c:(.text+0x474): undefined reference to `CPXgetnumrows'
mipex1.c:(.text+0x490): undefined reference to `CPXgetnumcols'
mipex1.c:(.text+0x4be): undefined reference to `CPXgetx'
mipex1.c:(.text+0x51c): undefined reference to `CPXgetslack'
mipex1.c:(.text+0x5f9): undefined reference to `CPXwriteprob'
mipex1.c:(.text+0x64d): undefined reference to `CPXfreeprob'
mipex1.c:(.text+0x697): undefined reference to `CPXcloseCPLEX'
mipex1.c:(.text+0x6e3): undefined reference to `CPXgeterrorstring'
collect2: error: ld returned 1 exit status

回答1:

The order of appearance of the library matters. Change your compilation statement to

gcc -I/opt/cplex-studio-125/cplex/include mipex1.c L/opt/cplex-studio-125/cplex/lib/x86-64_sles10_4.1/static_pic -lcplex

(Generic version)

gcc -I/<path> -L<path> <source.c> -l<lib>

to put the library after the source file, so that, linker will search the library for the function called from the source file.