code: plan9front

ref: e72da62915b09d5673b0c0179ba8dfe045aeb8c3
dir: /sys/src/libstdio/ftello.c/

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/*
 * pANS stdio -- ftello
 */
#include "iolib.h"
long long ftello(FILE *f){
	long long seekp=seek(f->fd, 0L, 1);
	if(seekp<0) return -1;		/* enter error state? */
	switch(f->state){
	default:
		return seekp;
	case RD:
		return seekp-(f->wp-f->rp);
	case WR:
		return (f->flags&LINEBUF?f->lp:f->wp)-f->buf+seekp;
	}
}