xref: /csrg-svn/usr.bin/f77/libU77/fseek_.c (revision 2530)
1*2530Sdlw /*
2*2530Sdlw char id_fseek[] = "@(#)fseek_.c	1.1";
3*2530Sdlw  *
4*2530Sdlw  * position a file associated with a fortran logical unit
5*2530Sdlw  *
6*2530Sdlw  * calling sequence:
7*2530Sdlw  *	ierror = fseek(lunit, ioff, ifrom)
8*2530Sdlw  * where:
9*2530Sdlw  *	lunit is an open logical unit
10*2530Sdlw  *	ioff is an offset in bytes relative to the position specified by ifrom
11*2530Sdlw  *	ifrom	- 0 means 'beginning of the file'
12*2530Sdlw  *		- 1 means 'the current position'
13*2530Sdlw  *		- 2 means 'the end of the file'
14*2530Sdlw  *	ierror will be 0 if successful, a system error code otherwise.
15*2530Sdlw  */
16*2530Sdlw 
17*2530Sdlw #include	<stdio.h>
18*2530Sdlw #include	"../libI77/f_errno.h"
19*2530Sdlw #include	"../libI77/fiodefs.h"
20*2530Sdlw 
21*2530Sdlw extern unit units[];
22*2530Sdlw 
23*2530Sdlw long fseek_(lu, off, from)
24*2530Sdlw long *lu, *off, *from;
25*2530Sdlw {
26*2530Sdlw 	if (*lu < 0 || *lu >= MXUNIT || *from < 0 || *from > 2)
27*2530Sdlw 		return((long)(errno=F_ERARG));
28*2530Sdlw 	if (!units[*lu].ufd)
29*2530Sdlw 		return((long)(errno=F_ERNOPEN));
30*2530Sdlw 	if (fseek(units[*lu].ufd, *off, (int)*from) < 0)
31*2530Sdlw 		return((long)errno);
32*2530Sdlw 	return(0L);
33*2530Sdlw }
34