github.com/afumu/libc@v0.0.6/musl/src/stdio/fileno.c (about)

     1  #include "stdio_impl.h"
     2  #include <errno.h>
     3  
     4  int fileno(FILE *f)
     5  {
     6  	FLOCK(f);
     7  	int fd = f->fd;
     8  	FUNLOCK(f);
     9  	if (fd < 0) {
    10  		errno = EBADF;
    11  		return -1;
    12  	}
    13  	return fd;
    14  }
    15  
    16  weak_alias(fileno, fileno_unlocked);