perror(3C)																perror(3C)

NAME

       perror(), strerror(), strerror_r() - write system error messages

SYNOPSIS

DESCRIPTION

       writes  a  language-dependent  message  to  the	standard  error output, describing the last error encountered during a call to a system or
       library function.  The argument string s is printed first, followed by a colon, a blank, the message, and a newline character.  To be  most
       useful,	the  argument  string  should  include the name of the program that incurred the error.  The error number is taken from the symbol
       which is set when errors occur but not cleared when non-erroneous calls are made.  The contents	of  the  message  is  identical  to  those
       returned by the function with as the argument.  If given a NULL string, the function prints only the message and a newline character.

       To simplify variant formatting of messages, the function and the array of message strings are provided.	The function maps the error number
       in errnum to a language-dependent error message string and returns a pointer to the string.  The message string is returned without a  new-
       line  character.  can be used as an index into to get an untranslated message string without the newline character.  is the largest message
       number provided for in the table; it should be checked because new error codes might be added to the system before they are  added  to  the
       table.  must be used to retrieve messages when translations are desired.

       The  function maps the error number in errnum to a locale-dependent error message string and returns the string in the buffer pointed to by
       buffer, which has length buflen.

EXTERNAL INFLUENCES

   Environment Variables
       The language of the message returned by and printed by is specified by the environment variable.  If the language-dependent message is  not
       available,  or  if  is  not  set  or  is  set to the empty string, the default version of the message associated with the "C" language (see
       lang(5)) is used.

   International Code Set Support
       Single and multi-byte character code sets are supported.

RETURN VALUE

       returns no value.

       If the errnum message number is valid, returns a pointer to a language-dependent message string.  The array pointed to should not be  modi-
       fied  by the program, and might be overwritten by a subsequent call to the function.  If a valid errnum message number does not have a cor-
       responding language-dependent message, uses errnum as an index into to get the message string.  If the errnum message  number  is  invalid,
       returns a pointer to a NULL string.

       Upon successful completion, returns 0.  Otherwise, an error number is returned to indicate the error.

ERRORS

       If the function fails, it will return one of the following errors:

	      The value of   errnum is not a valid error number.

	      Insufficient storage was supplied via
			     buffer and buflen to contain the generated message string.

WARNINGS

       The return value for points to data whose content is overwritten by subsequent calls to from the same thread.

SEE ALSO

       errno(2), lang(5), environ(5), thread_safety(5).

STANDARDS CONFORMANCE

																	perror(3C)