CODEWITHSUNDEEP
cshared-libraries
elo
elo

Reputation: 531

How does program finds symbols in dynamic library?

Let's say I have 3 files main.c, mylib.h and mylib.c.

main.c:

#include <stdio.h>
#include "mylib.h"

int main(int argc, char **argv) {
    printf("%d\n", foo());
}

mylib.h:

#pragma once

int foo();

mylib.c:

#include "mylib.h"

int foo() { return 5; }

If I build mylib as dynamic library and link it to main, main will have dynamic reference to it:

>>> ldd main                                                                                                                
...
libmylib.so => /some_path/libmylib.so
...

I found out if I change mylib.c, rebuild mylib and foo symbol address will change, I don't need to rebuild / link again my main program.

Does symbol lookup happen in runtime as if I loaded library using dlopen and no external symbol addresses are stored in main program?

Upvotes: 0

Views: 90

Answers (1)

Eric Postpischil
Eric Postpischil

Reputation: 222224

Does symbol lookup happen in runtime as if I loaded library using dlopen and no external symbol addresses are stored in main program?

Yes.

Upvotes: 1

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