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─────Run-Time Library───────────────────────────────────────────────────────
 
/* IOTEST.C compares low-level and stream I/O using function:
 *      _fdopen
 */
 
#include <io.h>
#include <fcntl.h>          /* _O_ constant definitions */
#include <sys\types.h>
#include <sys\stat.h>       /* _S_ constant definitions */
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
 
void main( int argc, char *argv[] )
{
    int  handle;
    FILE *stream;
    clock_t start;
    char tmp[16];
 
    /* Open for low-level I/O and read file in 16-byte chunks. */
    if( (handle = _open( argv[1], _O_BINARY | _O_RDONLY )) == - 1 )
        exit( 1 );
    start = clock();
    while( !_eof( handle ) )
        _read( handle, tmp, 16 );
    printf( "I/O Type: Low level\tTime: %5.1f\n",
             ((float)clock() - start) / CLOCKS_PER_SEC );
 
    /* Change to stream I/O and read file in 16-byte chunks. */
    if( (stream = _fdopen( handle, "rb" )) == NULL )
        exit( 1 );
    while( !feof( stream ) )
        fread( tmp, sizeof( char ), 16, stream );
    printf( "I/O Type: Stream\tTime: %5.1f\n",
             ((float)clock() - start) / CLOCKS_PER_SEC );
    _close( handle );
    exit( 0 );
}
                                    -♦-