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:
s
, followed by ": "
(unless s
is a null pointer or the character pointed to by s
is the null character) errno
, followed by '\n'
. The error message string is identical to the result of std::strerror(errno)
. s | - | pointer to a null-terminated string with explanatory message |
(none).
#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
macro which expands to POSIX-compatible thread-local error number variable (macro variable) |
|
returns a text version of a given error code (function) |
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