C/stdio.h/fflush
fflush: force the buffer contents to be written to the file
<source lang="cpp">
//Header: #include <stdio.h> //Declaration: int fflush(FILE *stream); //Return: 0 on success or EOF on error.
#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; } </source>