Question

How to use clearerr to reset the error flags and the EOF indicator for the given file stream in C

Answer 1

#include <stdio.h>
#include <assert.h>

int main(void)
{
    FILE* tmpf = tmpfile();

    fputs("text in file\n", tmpf);
    rewind(tmpf);

    for (int ch; (ch = fgetc(tmpf)) != EOF; putchar(ch)) {}

    assert(feof(tmpf)); // the for loop above terminate by EOF
    puts("End of file reached");

    clearerr(tmpf); // clear EOF

    puts(feof(tmpf) ? "EOF set" : "EOF cleared");
}





/*
run:

text in file
End of file reached
EOF cleared

*/

 

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