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.
