Thread: How to reuse a certain function in a large C project

Hi all

I want to ask what I should do to conviently reuse(include, compile and build executable) a certain function in a large C project that doesn't expose it

For example, I want to use function defined here postgres/fe-auth-scram.c at master * postgres/postgres * GitHubin this way:

Code:

// mycode.c

#include <stdlib.h>
// what else should I include?

int main() {
     char* pass = (char*) malloc(sizeof(char) * 1000);
     pass = pg_fe_scram_build_secret("testpassword");
}

I'm really a beginner in C and work on Linux platform
only know there is compile, link procedure when using gcc(not learned compilation theory)
but don't know how to design a gcc command that could let me write less code to reuse that function

thanks in advance!

Originally Posted by laserlight

The function is declared in fe-auth.h, so I don't see what's the problem: just include that header and link appropriately.

sry, my bad for not making this question clear

so my way of doing this now:
1. download from PostgreSQL: File Browser2. unpack it and ./configure then make
3. now write my code as
...
#include "fe-auth.h"
const char* pass_hash = pg_fe_scram_build_verifier("testpassword");
...
4. gcc -c mycode.c -I all_the_includes
5. but I don't know what to link to
a gcc -o result mycode.o
would throw a lot of undefined errors


what sould I do then?

use vscode find in file to find definition and relevant .o then link them one by one?
any tools to do it automatically for me?

thanks

First: Read the INSTALL file...

Check what header file declares the function in INCLUDE_DIR
Check which library to use in LIB_DIR