Undefined reference - despite lib being found by linker

Question

I have a trivial program to test for availability of python development files:

#include
int main(){Py_Initialize(); Py_Finalize(); }
<         


        

Answer 1

Try:

gcc -I/usr/include/python2.7 p.c -lpython2.7 

the linker doesn't yet know that Py_Initialize is a required symbol when it loads libpython2.7.a, so it tosses it away. And then it gets to p.o and throws a fit about the missing symbol. Ordering it this way will let the linker look for the missing symbol in subsequent inputs.

See: http://gcc.gnu.org/onlinedocs/gcc/Link-Options.html

It makes a difference where in the command you write this option; the linker searches and processes libraries and object files in the order they are specified. Thus, foo.o -lz bar.o' searches libraryz' after file foo.o but before bar.o. If bar.o refers to functions in `z', those functions may not be loaded.