exit

void exit( int exit_code );

_Noreturn void exit( int exit_code );

Causes normal program termination to occur.

Several cleanup steps are performed:

• functions passed to atexit are called, in reverse order of registration
• all C streams are flushed and closed
• files created by tmpfile are removed
• control is returned to the host environment. If exit_code is zero or EXIT_SUCCESS, an implementation-defined status, indicating successful termination is returned. If exit_code is EXIT_FAILURE, an implementation-defined status, indicating unsuccessful termination is returned. In other cases implementation-defined status value is returned.

Notes

The functions registered with at_quick_exit are not called.

The behavior is undefined if a program calls exit more than once, or if it calls exit and quick_exit.

The behavior is undefined if during a call to a function registered with atexit, the function exits with longjmp.

Returning from the the main function, either by a return statement or by reaching the end of the function, executes exit(), passing the argument of the return statement (or ​0​ if implicit return was used) as exit_code.

Parameters

Return value

(none).

Example

#include <stdio.h>
#include <stdlib.h>
 
int main(void)
{
    FILE *fp = fopen("data.txt","r");
    if (fp == NULL) {
       fprintf(stderr, "error opening file data.txt in function main()\n");
       exit( EXIT_FAILURE );
    }
    fclose(fp);
    printf("Normal Return\n");
    return EXIT_SUCCESS ;
}

error opening file data.txt in function main()

References

• C17 standard (ISO/IEC 9899:2018):
• 7.22.4.4 The exit function (p: 256)
• C11 standard (ISO/IEC 9899:2011):
• 7.22.4.4 The exit function (p: 351-352)
• C99 standard (ISO/IEC 9899:1999):
• 7.20.4.3 The exit function (p: 315-316)
• C89/C90 standard (ISO/IEC 9899:1990):
• 4.10.4.3 The exit function

See also