std::perror
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perror
Operations on files
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, 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 std::strerror (errno).
Contents
[edit] Parameters
s
-
pointer to a null-terminated string with explanatory message
[edit] Return value
(none)
[edit] Example
Run this code
#include <cerrno> #include <cmath> #include <cstdio> int main() { double not_a_number = std::log (-1.0); if (errno == EDOM ) std::perror("log(-1) failed"); std::printf ("%f\n", not_a_number); }
Possible output:
log(-1) failed: Numerical argument out of domain nan
[edit] See also
C documentation for perror