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perror

From cppreference.com
< c‎ | io
 
 
File input/output


Functions
File access
Direct input/output
Unformatted input/output
(C95)(C95)
(C95)
(C95)(C95)
(C95)
(C95)
Formatted input
Formatted output
File positioning
Error handling
perror
Operations on files
 
Defined in header <stdio.h>
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'.

Contents

[edit] Parameters

s - pointer to a null-terminated string with explanatory message

[edit] Return value

(none)

[edit] Example

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

Output:

open(): 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):

[edit] See also

returns a text version of a given error code
(function) [edit]