I make simple program in C which uses
glib.h, but when I compile it I get an error like:
$ gcc test.c -o test test.c:3:18: fatal error: glib.h: No such file or directory compilation terminated.
So from above it seems GCC can’t find
glib.h file (which is a part of the
libglib2.0-dev package and have already installed it). So first I try locate
glib.h files in my system and found output as below:
$ locate glib.h /usr/src/linux-headers-3.2.0-29-generic-pae/include/config/blk/dev/bsglib.h /usr/src/linux-headers-3.2.0-48-generic-pae/include/config/blk/dev/bsglib.h /usr/src/linux-headers-3.2.0-57-generic-pae/include/config/blk/dev/bsglib.h
then I have tried command:
$ pkg-config --cflags glib-2.0 -I/usr/include/glib-2.0 -I/usr/lib/i386-linux-gnu/glib-2.0/include
to get the right flags for GCC, but still it shows the same error.
So I have tried to find a solution from SO and found an exact solution like:
$ gcc test.c -Wall -o test `pkg-config --cflags --libs glib-2.0`
This command solves my problem.
But is there a way to tell GCC to include the glib library, so not to require to give the flag
pkg-config --cflags --libs glib-2.0 after
gcc and simply I compile my file by
gcc test.c -o test?
The problem of looking at C source code and figuring out which libraries it uses is very hard. It feels kind of "AI complete" to me, which is why it’s typically solved manually by the programmer pointing out the exact right libraries to satisfy the dependencies with.
Just for glib, it’s easy to imagine a system with both glib 1.x and 2.x versions installed, and some calls are named exactly the same. Now try to imagine a computer program capable of deducing what you meant, which library to link with. It’s not possible, since only the programmer knows.
pkg-config tool helps with the mechanics of what each library requires in order to be used, but it’s still up to you to tell it (via the module name argument(s)) which exact libraries to use.
Answered By – unwind