PERROR(2) PERROR(2)
NAME
perror, syslog, sysfatal - system error messages
SYNOPSIS
#include <u.h>
#include <libc.h>
void perror(char *s)
void syslog(int cons, char *logname, char *fmt, ...)
void sysfatal(char *fmt, ...)
DESCRIPTION
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 s is printed, then a
colon, then the message and a newline. If s is nil, only
the error message and newline are printed.
Syslog logs messages in the file named by logname in the
directory /sys/log; the file must already exist and should
be append-only. Logname must contain no slashes. The mes-
sage is a line with several fields: the name of the machine
writing the message; the date and time; the message speci-
fied by the print(2) format fmt and any following arguments;
and a final newline. If cons is set or the log file cannot
be opened, the message is also printed on the system con-
sole. Syslog can be used safely in multi-threaded programs.
Sysfatal prints to standard error the name of the running
program, a colon and a space, the message described by the
print(2) format string fmt and subsequent arguments, and a
newline. It then calls exits(2) with the formatted message
as argument. The program's name is the value of argv0,
which will be set if the program uses the arg(2) interface
to process its arguments. If argv0 is null, it is ignored
and the following colon and space are suppressed.
SOURCE
/sys/src/libc/port/perror.c
/sys/src/libc/9sys/syslog.c
/sys/src/libc/9sys/sysfatal.c
SEE ALSO
intro(2), errstr(2), the %r format in print(2)
BUGS
Perror is a holdover; the %r format in print(2) is pre-
ferred.
Page 1 Plan 9 (printed 11/22/24)