_IO_seekoff_unlocked
pos = _IO_seekoff_unlocked (fp, 0, _IO_seek_cur, 0);
pos = _IO_seekoff_unlocked (fp, 0, _IO_seek_cur, 0);
pos = _IO_seekoff_unlocked (fp, 0, _IO_seek_cur, 0);
(_IO_seekoff_unlocked (__fp, __offset, __whence, _IOS_INPUT|_IOS_OUTPUT) \
(void) _IO_seekoff_unlocked (FILE, 0, 0, _IOS_INPUT|_IOS_OUTPUT)
retval = _IO_seekoff_unlocked (fp, offset, dir, mode);
extern _IO_off64_t _IO_seekoff_unlocked (_IO_FILE *, _IO_off64_t, int, int)