STRERROR(3C) Standard C Library Functions STRERROR(3C)
NAME
strerror, strerror_r, strerror_l - get error message string
SYNOPSIS
#include <string.h>
char *strerror(
int errnum);
int strerror_r(
int errnum,
char *strerrbuf,
size_t buflen);
char *strerror_l(
int errnum,
locale_t loc);
DESCRIPTION
The
strerror() function maps the error number in
errnum to an error
message string, and returns a pointer to that string. It uses the same
set of error messages as
perror(3C). The returned string should not be
overwritten.
The
strerror_r() function maps the error number in
errnum to an error
message string and returns the string in the buffer pointed to by
strerrbuf with length
buflen.
The
strerror_l() function maps the error number in
errnum to an error
message string in the locale indicated by
loc. The returned string
should not be overwritten. If
loc is passed the
NULL pointer, then the
locale of the calling thread's current locale will be used instead.
Because the
strerror() and
strerror_l() functions, return localized
strings in the event of an unknown error, one must use the value of
errno to detect an error. Callers should first set
errno to
0 before the call
to either function and then check the value of
errno after the call. If
the value of
errno is non-zero then an error has occurred.
RETURN VALUES
Upon successful completion,
strerror() and
strerror_l() return a pointer
to the generated message string. Otherwise, they set
errno and returns a
pointer to an error message string. They return the localized string
"Unknown error" if
errnum is not a valid error number.
Upon successful completion,
strerror_r() returns 0. Otherwise it sets
errno and returns the value of
errno to indicate the error. It returns
the localized string "Unknown error" in the buffer pointed to by
strerrbuf if
errnum is not a valid error number.
ERRORS
These functions may fail if:
EINVAL The value of
errnum is not a valid error number.
The
strerror_r() function may fail if:
ERANGE The
buflen argument specifies insufficient storage to contain
the generated message string.
USAGE
Messages returned from these functions are in the native language
specified by the
LC_MESSAGES locale category. See
setlocale(3C) and
uselocale(3C).
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
|MT-Level | Safe |
+--------------------+-----------------+
SEE ALSO
gettext(3C),
perror(3C),
setlocale(3C),
uselocale(3C),
attributes(7),
standards(7) August 17, 2015
STRERROR(3C)