[unix-history] / usr / man / man3 / perror.3

.TH PERROR 3 
.SH NAME
perror, sys_errlist, sys_nerr \- system error messages
.SH SYNOPSIS
.B perror(s)
.br
.B char *s;
.PP
.B int sys_nerr;
.br
.B char *sys_errlist[];
.SH DESCRIPTION
.I Perror
produces a short error message
on the standard error file
describing the last error encountered during a call
to the system from a C program.
First the argument string
.I 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
.I errno
(see
.IR intro (2)),
which is set when errors occur but not cleared when
non-erroneous calls are made.
.PP
To simplify variant formatting
of messages, the vector of message strings
.I sys_errlist
is provided;
.I errno
can be used as an index in this table to get the
message string without the newline.
.I Sys_nerr
is the number of messages 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.
.SH "SEE ALSO"
intro(2)
Commit	Line	Data
c4665c80 TL	1	.TH PERROR 3
	2	.SH NAME
	3	perror, sys_errlist, sys_nerr \- system error messages
	4	.SH SYNOPSIS
	5	.B perror(s)
	6	.br
	7	.B char *s;
	8	.PP
	9	.B int sys_nerr;
	10	.br
	11	.B char *sys_errlist[];
	12	.SH DESCRIPTION
	13	.I Perror
	14	produces a short error message
	15	on the standard error file
	16	describing the last error encountered during a call
	17	to the system from a C program.
	18	First the argument string
	19	.I s
	20	is printed, then a colon, then the message and a new-line.
	21	Most usefully, the argument string is the name
	22	of the program which incurred the error.
	23	The error number is taken from the external variable
	24	.I errno
	25	(see
	26	.IR intro (2)),
	27	which is set when errors occur but not cleared when
	28	non-erroneous calls are made.
	29	.PP
	30	To simplify variant formatting
	31	of messages, the vector of message strings
	32	.I sys_errlist
	33	is provided;
	34	.I errno
	35	can be used as an index in this table to get the
	36	message string without the newline.
	37	.I Sys_nerr
	38	is the number of messages provided for in the table;
	39	it should be checked because new
	40	error codes may be added to the system before
	41	they are added to the table.
	42	.SH "SEE ALSO"
	43	intro(2)