37 lines
689 B
C
37 lines
689 B
C
#if !defined(lint) && defined(SCCSIDS)
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static char sccsid[] = "@(#)ftell.c 1.1 92/07/30 SMI"; /* from S5R2 1.2 */
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#endif
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/*LINTLIBRARY*/
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/*
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* Return file offset.
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* Coordinates with buffering.
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*/
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#include <stdio.h>
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extern long lseek();
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long
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ftell(iop)
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register FILE *iop;
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{
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register long tres;
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register int adjust;
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if(iop->_cnt < 0)
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iop->_cnt = 0;
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if(iop->_flag & _IOREAD)
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adjust = - iop->_cnt;
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else if(iop->_flag & (_IOWRT | _IORW)) {
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adjust = 0;
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if(iop->_flag & _IOWRT && iop->_base &&
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(iop->_flag & _IONBF) == 0)
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adjust = iop->_ptr - iop->_base;
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} else
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return(-1);
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tres = lseek(fileno(iop), 0L, 1);
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if(tres >= 0)
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tres += (long)adjust;
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return(tres);
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}
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