ref: 2ec9006e9ef02e5e13ff51eaabac23b9695ed113
dir: /sys/src/libstdio/ftell.c/
/*
* pANS stdio -- ftell
*/
#include "iolib.h"
long ftell(FILE *f){
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;
}
}