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  PERROR(3C)      (C Programming Language Utilities)     PERROR(3C)



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

  SYNOPSIS
       void perror (s)
       char *s;

       extern int errno;

       extern char *syserrlist[ ];

       extern int sysnerr;

  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.  (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).








  Page 1                                                   May 1989