xref: /plan9-contrib/sys/src/libstdio/ftello.c (revision 22df390c30710ddd2119f3e7bb6c92dc399cabb9)
1dc5a79c1SDavid du Colombier /*
2dc5a79c1SDavid du Colombier  * pANS stdio -- ftello
3dc5a79c1SDavid du Colombier  */
4dc5a79c1SDavid du Colombier #include "iolib.h"
ftello(FILE * f)5dc5a79c1SDavid du Colombier long long ftello(FILE *f){
6*22df390cSDavid du Colombier 	long long seekp=seek(f->fd, 0, SEEK_CUR);
7dc5a79c1SDavid du Colombier 	if(seekp<0) return -1;		/* enter error state? */
8dc5a79c1SDavid du Colombier 	switch(f->state){
9dc5a79c1SDavid du Colombier 	default:
10dc5a79c1SDavid du Colombier 		return seekp;
11dc5a79c1SDavid du Colombier 	case RD:
12dc5a79c1SDavid du Colombier 		return seekp-(f->wp-f->rp);
13dc5a79c1SDavid du Colombier 	case WR:
14dc5a79c1SDavid du Colombier 		return (f->flags&LINEBUF?f->lp:f->wp)-f->buf+seekp;
15dc5a79c1SDavid du Colombier 	}
16dc5a79c1SDavid du Colombier }
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