


      PERROR(3C)                  (UNIX 5.0)                 PERROR(3C)



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

      SYNTAX
           void perror (s)
           char *s;

           extern int errno;

           extern char *sys_errlist[ ];

           extern int sys_nerr;

      DESCRIPTION
           Perror 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.  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 in this table to get the message string without
           the new-line.  Sys_nerr is the largest message number
           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.

      SEE ALSO
           intro(2).





















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