r
- rad2deg()
- rand()
- range()
- rawurldecode()
- rawurlencode()
- read_exif_data()
- readdir()
- readfile()
- readgzfile()
- readline()
- readline_add_history()
- readline_clear_history()
- readline_completion_function()
- readline_info()
- readline_list_history()
- readline_read_history()
- readline_write_history()
- readlink()
- realpath()
- recode()
- recode_file()
- recode_string()
- register_shutdown_function()
- register_tick_function()
- rename()
- reset()
- restore_error_handler()
- rewind()
- rewinddir()
- rmdir()
- round()
- rsort()
- rtrim()
