xref: /inferno-os/lib9/vfprint.c (revision 1f44c82a26ff60e012a2ff697cb036a25c0c7f97)
1 /*
2  * The authors of this software are Rob Pike and Ken Thompson.
3  *              Copyright (c) 2002 by Lucent Technologies.
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose without fee is hereby granted, provided that this entire notice
6  * is included in all copies of any software which is or includes a copy
7  * or modification of this software and in all copies of the supporting
8  * documentation for such software.
9  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
10  * WARRANTY.  IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
11  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
12  * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
13  */
14 #include "lib9.h"
15 #include "fmtdef.h"
16 
17 /*
18  * generic routine for flushing a formatting buffer
19  * to a file descriptor
20  */
21 int
_fmtFdFlush(Fmt * f)22 _fmtFdFlush(Fmt *f)
23 {
24 	int n;
25 
26 	n = (char*)f->to - (char*)f->start;
27 	if(n && write((int)f->farg, f->start, n) != n)
28 		return 0;
29 	f->to = f->start;
30 	return 1;
31 }
32 
33 int
vfprint(int fd,char * fmt,va_list args)34 vfprint(int fd, char *fmt, va_list args)
35 {
36 	Fmt f;
37 	char buf[256];
38 	int n;
39 
40 	fmtfdinit(&f, fd, buf, sizeof(buf));
41 	va_copy(f.args, args);
42 	n = dofmt(&f, fmt);
43 	va_end(f.args);
44 	if(n > 0 && _fmtFdFlush(&f) == 0)
45 		return -1;
46 	return n;
47 }
48