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

int main(int argc, char* argv[]) {
    // If we call this as:  $ ./stderr_stdout > stderr_stdout.txt
    fputc('A', stdout);  // … this
    fputc('\n', stdout); // … and this will be redirected to the file.
    fprintf(stderr, "# LOG:  Printed an 'A' ↑↑↑\n");  // This will still be shown on the
                                                      // terminal and not in the file.
    return EXIT_SUCCESS;
}
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