PERROR(3C)           INTERACTIVE UNIX System           PERROR(3C)



          NAME
               perror, errno, sys_errlist, sys_nerr - system error messages

          SYNOPSIS
               void perror (s)
               char *s;

               extern int errno;

               extern char *sys_errlist[ ];

               extern int sys_nerr;

          DESCRIPTION
               The perror function produces a message on 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, then a colon and a blank, then the message
               and a new-line.  (However, if s="", the colon is not
               printed.)  To be of most use, the argument string should
               include the name of the program that incurred the error.
               The error number is taken from the external variable errno,
               which is set when errors occur but not cleared when non-
               erroneous calls are made.

               To simplify variant formatting of messages, the array of
               message strings sys_errlist is provided; errno can be used
               as an index into this table to get the message string
               without the new-line.  Sys_nerr is the number of messages in
               the table; it should be checked because new error codes may
               be added to the system before they are added to the table.

          SEE ALSO
               intro(2).





















          Rev. C Software Development Set                            Page 1