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

.TH PERROR 3  "19 January 1983"
.UC 4
.SH NAME
perror, sys_errlist, sys_nerr \- system error messages
.SH SYNOPSIS
.nf
.B perror(s)
.B char *s;
.PP
.B int sys_nerr;
.B char *sys_errlist[];
.fi
.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),
psignal(3)
Commit	Line	Data
0164e195 C	1	.TH PERROR 3 "19 January 1983"
	2	.UC 4
	3	.SH NAME
	4	perror, sys_errlist, sys_nerr \- system error messages
	5	.SH SYNOPSIS
	6	.nf
	7	.B perror(s)
	8	.B char *s;
	9	.PP
	10	.B int sys_nerr;
	11	.B char *sys_errlist[];
	12	.fi
	13	.SH DESCRIPTION
	14	.I Perror
	15	produces a short error message 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 of messages, the vector of message strings
	31	.I sys_errlist
	32	is provided;
	33	.I errno
	34	can be used as an index in this table to get the
	35	message string without the newline.
	36	.I Sys_nerr
	37	is the number of messages provided for in the table;
	38	it should be checked because new error codes may be added to the system before
	39	they are added to the table.
	40	.SH "SEE ALSO"
	41	intro(2),
	42	psignal(3)