swatt (08/10/82)
Several people have requested this; it's quite short so I'm posting it
here (it's also amazingly cheap; "_doprnt" does all the work!).
The function names "error" and "remark" are, of course, gleaned from
Software Tools. They work in a similar manner, appending a newline at
the end. Thus:
error ("Too many files (%d); max is %d", nfiles, MAXFILES);
is all you need. The format string accepted by error and remark (and
fperror, and fpremark) is the same as for printf. Variable number of
arguments works the same way as well.
fperror, is just like error, except that it appends the standard system
error message (like perror). fpremark is just like remark with the
same addition.
I don't believe it depends on 4.1bsd stdio internals, but I could be
wrong. I seem to recall moving this stuff to an ONYX but if so it was
a long time ago and I may be fooling myself. It just occurred to me
people on system III **might** have a different formatted print
function; I've made this stuff work under IS/1 (derivative of PWB), and
there were minor differences. If anyone has trouble, I can dig up the
differences and post them as well.
- Alan S. Watt
======================================================================
sed 's/^ //' >error.c <<!EOF
/*********************************************************************
function: error
description: Error message routines
programmer: Alan S. Watt
history:
11/04/81 original version
07/17/82 fixes for lint
08/10/82 modest cleanup before posting.
*********************************************************************/
#ifndef lint
static char Sccsid[] = "@(#)error.c 1.1";
#endif !lint
#include <stdio.h>
#define NOTOK (-1)
/* VARARGS1 */
error (mesg, args)
char *mesg;
{
_doprnt (mesg, &args, stderr);
putc ('\n', stderr);
exit (NOTOK);
}
extern errno;
extern sys_nerr;
extern char *sys_errlist[];
#ifdef lint
int errno;
int sys_nerr;
char *sys_errlist[1];
#endif lint
static char ehuh[] = "Unknown System Error";
/* VARARGS1 */
fperror (mesg, args)
char *mesg;
{
char *err = ((unsigned)errno >= sys_nerr ? ehuh : sys_errlist[errno]);
_doprnt (mesg, &args, stderr);
fprintf (stderr, ": %s\n", err);
exit (NOTOK);
}
/*VARARGS1*/
remark (mesg, args)
char *mesg;
{
_doprnt (mesg, &args, stderr);
putc ('\n',stderr);
}
/*VARARGS1*/
fpremark (mesg, args)
char *mesg;
{
char *err = ((unsigned)errno >= sys_nerr ? ehuh : sys_errlist[errno]);
_doprnt (mesg, &args, stderr);
fprintf (stderr, ":%s\n", err);
}
!EOF
sed 's/^ //' >error.3a <<!EOF
.\" Manual page for error(3a)
.\" author: Alan S. Watt
.\"
.\" Sccsid=@(#)error.3a 1.1
.\"
.\" To format this page:
.\" nroff -man
.\"
.\" history:
.\" 08/10/82 original version
.TH "error" 3a "Advanced Technology"
.ED "8/10/82"
.SH NAME
error \- formatted print diagnostic functions
.SH SYNOPSIS
.nf
.B error (format, arg, ...)
.sp
.B fperror (format, arg, ...)
.sp
.B remark (format, arg, ...)
.sp
.B fpremark (format, arg, ...)
.sp
.B char *format
.B int arg
.fi
.SH DESCRIPTION
All these functions directed a formatted message to the
.I standard error
channel (normally the user's terminal).
Both
.I error
and
.I fperror
force an exit with a status of -1 as well.
The
.I format
argument to all functions is exactly like the format
argument to
.IR printf .
The number of
arguments is variable, as with
.IR printf .
.PP
.I fperror
is like
.IR error ,
except that it also appends the standard
system error message (like
.IR perror (3)).
.I fpremark
is like
.IR remark ,
with the same addition.
If for any reason the external system error number
.RI ( errno )
is not valid, the message "Unknown System Error" is substituted.
.PP
.I format
need not contain a final newline character;
one is appended automatically.
The operating spirit for these functions is from
.I Software
.IR Tools .
.SH EXAMPLES
.IP ""
.nf
error ("Too many files (%d); max is %d", nfiles, MAXFILES);
if ((fd = fopen (file, "r")) == NULL)
fperror ("Cannot open %s for reading", file);
if (!exists (file))
remark ("Warning: %s does not exist, creating it", file);
.fi
.PP
The first example prints an error message and exits.
The second prints a diagnostic including the standard system
error message and exits.
The final example prints a diagnostic (advisory), but does not
exit.
.SH DIAGNOSTICS
.I error
and
.I fperror
both exit with the status -1.
.SH BUGS
.SH SEE ALSO
exit(2),
perror(3)
.SH AUTHOR
Alan S. Watt
.br
ittvax!swatt
!EOF