flush清空输入输出流

#include <string.h>

#include <stdio.h>

#include <conio.h>

#include <io.h>



void flush(FILE *stream);



int main(void)

{

    FILE *stream;

    char msg[] = "This is a test";

    /* create a file */

    stream = fopen("DUMMY.FIL", "w");

    /* write some data to the file */

    fwrite(msg, strlen(msg), 1, stream);

    printf("Press any key to flush DUMMY.FIL:");

    getch();

    /* flush the data to DUMMY.FIL without closing it */

    flush(stream);

    printf("\nFile was flushed, Press any key to quit:");

    getch();

    return 0;

}



void flush(FILE *stream)

{

    int duphandle;

    /* flush the stream's internal buffer */

    fflush(stream);

    /* make a duplicate file handle */

    duphandle = dup(fileno(stream));

    /* close the duplicate handle to flush the DOS buffer */

    close(duphandle);

}









#include <stdio.h>

#include <stdlib.h>



int main(void){

    FILE *fp;

    if((fp=fopen("test", "rb"))==NULL) {

        printf("Cannot open file.\n");

        exit(1);

    }

    char ch = 'C';

    int i;

    for(i=0; i<5; i++) {

        fwrite(ch, sizeof(ch), 1, fp);

        fflush(fp);

    }

    fclose(fp);

    return 0;

 }