Exit codes

Learn program exit codes with exit.

exit and return codes

When a C program ends it returns an exit code to the shell. 0 means success; any non-zero value signals an error. Two ways exist: return from main or call exit from <stdlib.h>.

exit(1) ends the program at once; remaining code never runs. return 1 only leaves main. exit is handy for escaping a deep call stack. The constants EXIT_SUCCESS and EXIT_FAILURE improve readability over raw 0 and 1. The shell checks the last exit code with $?.

Conditional exit

Calling exit on error prevents the program from entering an inconsistent state. When the condition holds, exit inside an if block skips the remaining code.

Example: if (error) { printf("Problem\n"); exit(1); }. Here, if error is true the program prints a message and stops at once; lines after exit never run. This pattern is common for operations that can fail such as file opening or memory allocation. exit flushes and closes open files and calls functions registered with atexit, giving a clean shutdown.

Exercise Write a conditional exit

Add #include <stdlib.h>. Declare int hata = 1;. Print printf("Başlıyor\n");. Inside an if (hata) block print printf("Sorun\n"); and call exit(1);. After the if, print printf("Bitti\n");.

Show example solution

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

int main(void) {
    int hata = 1;
    printf("Başlıyor\n");
    if (hata) {
        printf("Sorun\n");
        exit(1);
    }
    printf("Bitti\n");
    return 0;
}

Test yourself

Match the exit codes

0

Success
1

Error
exit(1)

Stop now
return 0

Leave main

Complete the exit call

if (status != 0) exit(____);

Show answer

if (status != 0) exit(1);

What happens to code after exit(1)?
- It keeps running
- It never runs
- It enters an infinite loop
- It triggers a compiler warning
Show answer

It never runs — exit(1) ends the program at once; subsequent code never runs.

Next lesson: Summary - Command line

We Are Enhancing Your Experience

Cookie Preferences

Strictly Necessary Cookies

Analytical Cookies