third_party/ulib/musl/src/stdio/fileno.c

#include "stdio_impl.h"

int fileno(FILE* f) {
    /* f->fd never changes, but the lock must be obtained and released
     * anyway since this function cannot return while another thread
     * holds the lock. */
    FLOCK(f);
    FUNLOCK(f);
    return f->fd;
}

weak_alias(fileno, fileno_unlocked);