clearerr

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
 
int main(void)
{
    FILE* tmpf = tmpfile();
    fputs("abcde\n", tmpf);
    rewind(tmpf);
    int ch;
    while ((ch=fgetc(tmpf)) != EOF)
          printf("%c", ch);
    assert(feof(tmpf)); // 此循环期待以 eof 终止
    puts("End of file reached");
 
    clearerr(tmpf);  // 清除 eof
 
    if (feof(tmpf))
        puts("EOF indicator set");
    else
        puts("EOF indicator cleared\n");
}