PERROR(III) 11/5/73 PERROR(III)
NAME
perror - 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
program. First the argument string s is printed, then a
colon, then the message and a new-line. 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 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
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
Introduction to System Calls
BUGS