perror

void perror( const char *s );

Prints to stderr the contents of the null-terminated character string pointed to by s (unless s is a null pointer), followed by the two characters ": ", followed by the implementation-defined error message describing the error code currently stored in the system variable errno (identical to the output of strerror(errno)), followed by '\n'.

Parameters

Return value

(none).

Example

#include <stdio.h>
 
int main(void)
{
    FILE* f = fopen("non_existent", "r");
    if (f == NULL) {
        perror("open()");
    } else {
        fclose(f);
    }
}

open(): No such file or directory

References

• C11 standard (ISO/IEC 9899:2011):
  • 7.21.10.4 The perror function (p: 339)
• C99 standard (ISO/IEC 9899:1999):
  • 7.19.10.4 The perror function (p: 305)
• C89/C90 standard (ISO/IEC 9899:1990):
  • 4.9.10.4 The perror function

See also