xref: /plan9/sys/src/libstdio/ftello.c (revision dc5a79c1208f0704eeb474acc990728f8b4854f5)
1*dc5a79c1SDavid du Colombier /*
2*dc5a79c1SDavid du Colombier  * pANS stdio -- ftello
3*dc5a79c1SDavid du Colombier  */
4*dc5a79c1SDavid du Colombier #include "iolib.h"
ftello(FILE * f)5*dc5a79c1SDavid du Colombier long long ftello(FILE *f){
6*dc5a79c1SDavid du Colombier 	long long seekp=seek(f->fd, 0L, 1);
7*dc5a79c1SDavid du Colombier 	if(seekp<0) return -1;		/* enter error state? */
8*dc5a79c1SDavid du Colombier 	switch(f->state){
9*dc5a79c1SDavid du Colombier 	default:
10*dc5a79c1SDavid du Colombier 		return seekp;
11*dc5a79c1SDavid du Colombier 	case RD:
12*dc5a79c1SDavid du Colombier 		return seekp-(f->wp-f->rp);
13*dc5a79c1SDavid du Colombier 	case WR:
14*dc5a79c1SDavid du Colombier 		return (f->flags&LINEBUF?f->lp:f->wp)-f->buf+seekp;
15*dc5a79c1SDavid du Colombier 	}
16*dc5a79c1SDavid du Colombier }
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