GNU ld cannot find library which is there
The packages I'm toying with here are rather unknown, but nevertheless the problem is rather generic. Basically, I'm trying to compile Python module (called rql) with C++ extension. The extension uses external framework called gecode, which contains several libraries. I compiled gecode and installed locally. Now, let the output speak for itself:
red@devel:~/build/rql-0.23.3$ echo $LD_LIBRARY_PATH
/home/red/usr/lib
red@devel:~/build/rql-0.23.3$ ls $LD_LIBRARY_PATH | grep libgecodeint
libgecodeint.so
libgecodeint.so.22
libgecodeint.so.22.0
red@devel:~/build/rql-0.23.3$ python setup.py build
running build
running build.py
package init file './test/__init__.py' not found (or not a regular file)
running build_ext
building 'rql_solve' extension
g++ -pthread -shared build/temp.linux-i686-2.5/gecode-solver.o -lgecodeint -lgecodekernel -lgecodesearch -o build/lib.linux-i686-2.5/rql_solve.so
/usr/bin/ld: cannot find -lgecodeint
collect2: ld returned 1 exit status
error: command 'g++' failed with exit status 1
Answer
LD_LIBRARY_PATH is for runtime linker/loader (same effect could be achieved with ldconfig ). What you need is the -L flag:
-L/home/red/usr/lib
on the compiler command line.
Edit:
And - thanks to @bjg for reminding me - you can use LIBRARY_PATH if you don't want to mess with compiler options.