如何使用共享库编译文件？

Question

I am trying to compile a source given a .so file libfoo.so . The only thing in this library is a function that just returns a number (yeah, I know, advanced stuff). The header file equivalent (I was provided with both, but am only supposed to use the .so) is named foo.h and the function is named int foo() .

My source file is main.c :

#include <stdio.h>

#include "foo.h"

int main()
{
    int x = foo();

    printf("%d", x);

    return 0;   
}

Now, when trying to compile I have the following commands:

gcc -Wall -fPIC -c main.c -o main.o

gcc -Wall -fPIC main.o -o main -lfoo -L.

The first command fails to create the object file, outputting the following error:

fatal error: foo.h: No such file or directory

I am using Ubuntu 16.04.

I have also tried exporting the current location to LD_LIBRARY_PATH as I've seen suggested on a few other answers.

export LD_LBIRARY_PATH=$LD_LIBRARY_PATH:machine/Desktop/lib_test

Answer 1

You need to have the interface definition from the .h file and that file must be in the current directory or a directory on the include search path.

Note that on some systems filenames and paths are case dependent.