ultrix man page for perror

perror(3)						     Library Functions Manual							 perror(3)

Name
       perror, strerror, sys_errlist, sys_nerr - system error messages

Syntax
       void perror(s)
       char *s;

       int sys_nerr;
       char *sys_errlist[];

       #include <string.h>

       char *strerror(err)
       int err;

Description
       The  subroutine produces a short error message on the standard error file describing the last error encountered during a call to the system
       from a C program.  First the argument string s , if it is not a null pointer, is printed followed by a colon and a space; then the  message
       and  a  new line are printed.  Most usefully, the argument string is the name of the program which incurred the error.  The error number is
       taken from the external variable errno which is set when errors occur but not cleared when nonerroneous calls are made.	For further infor-
       mation, see

       To  simplify  variant  formatting of messages, the vector of message strings sys_errlist is provided; errno can be used as an index in this
       table to get the message string without the new line.  The sys_nerr is the number of messages provided for  in  the  table;  it	should	be
       checked	because new error codes may be added to the system before they are added to the table.	The function will also return a pointer to
       the message text for a given error number.

See Also
       intro(2), psignal(3)

																	 perror(3)