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.