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

SYNOPSIS
     perror(s)
     char *s;

     int sys_nerr;
     char *sys_errlist[];

     int errno;

DESCRIPTION
     Perror produces a short error message describing the last
     error encountered during a call to the system from a C pro-
     gram.  First the argument string s is printed, then a colon,
     then the message and a new-line.  Most usefully, the argu-
     ment 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
     non-erroneous calls are made.

     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 newline.  Sys_nerr is the largest message number pro-
     vided 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
     Introduction to System Calls

BUGS

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