93 lines
1.8 KiB
Text
93 lines
1.8 KiB
Text
|
.TH PERROR 2
|
||
|
|
.SH NAME
|
||
|
|
perror, syslog, sysfatal \- system error messages
|
||
|
|
.SH SYNOPSIS
|
||
|
|
.B #include <u.h>
|
||
|
|
.br
|
||
|
|
.B #include <libc.h>
|
||
|
|
.PP
|
||
|
|
.B
|
||
|
|
void perror(char *s)
|
||
|
|
.PP
|
||
|
|
.B
|
||
|
|
void syslog(int cons, char *logname, char *fmt, ...)
|
||
|
|
.PP
|
||
|
|
.B
|
||
|
|
void sysfatal(char *fmt, ...)
|
||
|
|
.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.
|
||
|
|
First the argument string
|
||
|
|
.I s
|
||
|
|
is printed, then a colon, then the message and a newline.
|
||
|
|
If
|
||
|
|
.I s
|
||
|
|
is nil, only the error message and newline are printed.
|
||
|
|
.PP
|
||
|
|
.I Syslog
|
||
|
|
logs messages in the file named by
|
||
|
|
.I logname
|
||
|
|
in the directory
|
||
|
|
.BR /sys/log ;
|
||
|
|
the file must already exist and should be append-only.
|
||
|
|
.I Logname
|
||
|
|
must contain no slashes.
|
||
|
|
The message is a line with several fields:
|
||
|
|
the name of the machine writing the message;
|
||
|
|
the date and time;
|
||
|
|
the message specified by the
|
||
|
|
.IR print (2)
|
||
|
|
format
|
||
|
|
.I fmt
|
||
|
|
and any following arguments;
|
||
|
|
and a final newline.
|
||
|
|
If
|
||
|
|
.I cons
|
||
|
|
is set or the log file cannot be opened, the message is also printed
|
||
|
|
on the system console.
|
||
|
|
.I Syslog
|
||
|
|
can be used safely in multi-threaded programs.
|
||
|
|
.PP
|
||
|
|
.I Sysfatal
|
||
|
|
prints to standard error the name of the running program,
|
||
|
|
a colon and a space,
|
||
|
|
the message described by the
|
||
|
|
.IR print (2)
|
||
|
|
format string
|
||
|
|
.I fmt
|
||
|
|
and subsequent arguments, and a newline.
|
||
|
|
It then calls
|
||
|
|
.IR exits (2)
|
||
|
|
with the formatted message as argument.
|
||
|
|
The program's name is the value of
|
||
|
|
.BR argv0 ,
|
||
|
|
which will be set if the program uses the
|
||
|
|
.IR arg (2)
|
||
|
|
interface to process its arguments.
|
||
|
|
If
|
||
|
|
.B argv0
|
||
|
|
is null, it is ignored and the following colon and space are suppressed.
|
||
|
|
.SH SOURCE
|
||
|
|
.B /sys/src/libc/port/perror.c
|
||
|
|
.br
|
||
|
|
.B /sys/src/libc/9sys/syslog.c
|
||
|
|
.br
|
||
|
|
.B /sys/src/libc/9sys/sysfatal.c
|
||
|
|
.SH "SEE ALSO"
|
||
|
|
.IR intro (2),
|
||
|
|
.IR errstr (2),
|
||
|
|
the
|
||
|
|
.B %r
|
||
|
|
format in
|
||
|
|
.IR print (2)
|
||
|
|
.SH BUGS
|
||
|
|
.I Perror
|
||
|
|
is a holdover; the
|
||
|
|
.B %r
|
||
|
|
format in
|
||
|
|
.IR print (2)
|
||
|
|
is preferred.
|