perror - cppreference.com (original) (raw)

| | | | | ------------------------------ | | | | void perror( const char *s ); | | |

Prints a textual description of the error code currently stored in the system variable errno to stderr.

The description is formed by concatenating the following components:

• the contents of the null-terminated byte string pointed to by s, followed by ": " (unless s is a null pointer or the character pointed to by s is the null character)
• implementation-defined error message string describing the error code stored in errno, followed by '\n'. The error message string is identical to the result of strerror(errno).

[edit] Parameters

[edit] Return value

(none)

[edit] Example

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

Possible output:

fopen() failed: No such file or directory

[edit] 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

[edit] See also