46 lines
858 B
C
46 lines
858 B
C
/*
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* ftell.c - obtain the value of the file-position indicator of a stream
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*/
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/* $Header$ */
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#include <assert.h>
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#include <stdio.h>
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#if (SEEK_CUR != 1) || (SEEK_SET != 0) || (SEEK_END != 2)
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#error SEEK_* values are wrong
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#endif
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#include "loc_incl.h"
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#include <sys/types.h>
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off_t _lseek(int fildes, off_t offset, int whence);
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long ftell(FILE *stream)
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{
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assert(sizeof(long) == sizeof(off_t));
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return (long) ftello(stream);
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}
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off_t ftello(FILE *stream)
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{
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long result;
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int adjust = 0;
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if (io_testflag(stream,_IOREADING))
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adjust = -stream->_count;
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else if (io_testflag(stream,_IOWRITING)
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&& stream->_buf
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&& !io_testflag(stream,_IONBF))
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adjust = stream->_ptr - stream->_buf;
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else adjust = 0;
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result = _lseek(fileno(stream), (off_t)0, SEEK_CUR);
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if ( result == -1 )
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return result;
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result += (long) adjust;
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return result;
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}
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