fd <-> fp 변환

int fileno(FILE *stream);

FILE *fdopen(int fd, const char *mode);

[링크 : http://stackoverflow.com/.../how-can-i-convert-a-file-pointer-file-fp-to-a-file-descriptor-int-fd]

[링크 : http://stackoverflow.com/.../how-to-get-a-file-pointer-from-a-file-descriptor]

[링크 : https://linux.die.net/man/3/fileno]

[링크 : https://linux.die.net/man/3/fdopen]