How can I use chdir function in Linux?

Question

I have a question, here is my original code in the testchdir.c file:

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

int main(int argc,char **argv) 
{ 
    if (argc < 2)
    {
        printf("Usage: %s <pathname\n",argv[0]);
        exit(1);
    }

    if (chdir(argv[1]) == 0)
    {
        printf("success in chdir\n");
        return 0;
    }
    else
    {
        printf("error happened");
        exit(1);
    }
}

In my Linux system, my original path is /home/Tom3543, then when I compile my codes above using gcc -o testchdir testchdir.c, it looks good. Later on, I want to change my path and execute the program, so I type

./testchdir /home/tom3543/C++

"success in chdir" appeared in my terminal, but my path is still /home/Tom3543 in my terminal. Can someone help me explain why? I am confused about that!

Answer 1

It's because the shell starts a new process for your program, and you only change the current directory in that new process. The shells process will be unaffected.

Unfortunately (for you) there's no real good (or legal) way to change the working directory of the parent process (the process of the shell).