Defined in header
void perror( const char *s );
Prints to stderr the contents of the null-terminated character string pointed to by
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 std::strerror(errno)), followed by '\n'.
|s||-||pointer to a null-terminated string with explanatory message|
log(-1) failed: Numerical argument out of domain
C documentation for perror