[SOLVED] Why do I get an undefined reference to a symbol that is defined in the library I am linking?

Why do I get an undefined reference to a symbol that is defined in the library I am linking?

I was trying to compile an unrelated project when I got an undefined reference when using a specific function of the Raylib library.

I was able to reproduce this behaviour using the following test.c

#include <raylib.h>

int main(){
        InitWindow(500,500, "test");
        
        int w = GetRenderWidth(); // undefined reference symbol
                                                                                
        while(!WindowShouldClose()){                                            
                BeginDrawing();                                                 
                ClearBackground(BLACK);                                  
                EndDrawing();                                                   
        }                                                                       
        CloseWindow();                                                          
        return 0;                                                               
}

This code was compiled using the following command.

gcc test.c -o app -L/usr/local/lib -lraylib

The resulting output was

/usr/bin/ld: /tmp/ccxqgamX.o: in function `main':
code.c:(.text+0x27): undefined reference to `GetRenderWidth'
collect2: error: ld returned 1 exit status

Once I commented the offending line out however (// int w = GetRenderWidth();) The app compiled fine and also was able run succesfully.

I examined the libraylib.a library in my /usr/local/lib folder using

nm /usr/local/lib/libraylib.a | grep GetRenderWidth

This resulted in the following outputt:

0000000000027b1e T GetRenderWidth

From this I surmise that the symbol is actually present in the library I linked and thus my question. Why does my compiler (both gcc and clang) report an undefined reference on GetRenderWidth() but not on other symbols from the same library?

Solution

Turns out that /usr/local/lib also contained a shared version of the same library which my compilers linked with. This version did not contain the GetRenderWidth symbol which is what caused my confusion. I was able to force my compiler to use the static library by replacing -lraylib with -l:libraylib.a.