< cpp‎ | string‎ | byte
Defined in header <cstring>
char* strerror( int errnum );

Returns text version of the error code errnum. errnum is usually acquired from the errno variable, however the function accepts any value of type int. The message is locale-specific.

The returned byte string must not be modified by the program, but may be overwritten by a subsequent call to the strerror function.


[edit] Parameters

errnum - integral value referring to a error code

[edit] Return value

Pointer to a null-terminated byte string corresponding to the error code errnum.

[edit] Example

#include <iostream>
#include <cmath>
#include <cerrno>
#include <cstring>
int main()
    double not_a_number = std::log(-1.0);
    if (errno == EDOM) {
        std::cout << "log(-1) failed: " << std::strerror(errno) << '\n';


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

[edit] See also

macros for standard POSIX-compatible error conditions
(macro constant)
C documentation for strerror