std::perror - cppreference.com (original) (raw)

| | | | | ------------------------------ | | | | 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).

[edit] Parameters

[edit] Return value

(none)

[edit] Example

#include #include #include   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

| | 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] | | |