#### 21.4.6 Convert textual time and date information back

The ISO C standard does not specify any functions which can convert the output of the `strftime` function back into a binary format. This led to a variety of more-or-less successful implementations with different interfaces over the years. Then the Unix standard was extended by the addition of two functions: `strptime` and `getdate`. Both have strange interfaces but at least they are widely available.