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std::perror

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Revision as of 06:42, 26 September 2013 by 200.14.84.164 (Talk)

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Defined in header <cstdio>
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 (unless s is a null pointer)
  • ": "
  • implementation-defined error message describing the error code stored in errno. This message is identical to the output of std::strerror(errno).
  • '\n'.

Contents

[edit] Parameters

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

[edit] Return value

(none)

[edit] Example

#include <cmath>
#include <cerrno>
#include <cstdio>
 
int main()
{
    double not_a_number = std::log(-1.0);
    if (errno == EDOM) {
        std::perror("log(-1) failed");
    }
}

Output:

log(-1) failed: Numerical argument out of domain

[edit] See also

macro which expands to POSIX-compatible thread-local error number variable
(macro variable) [edit]
returns a text version of a given error code
(function) [edit]
C documentation for perror