GNU C Library (libc) Programming Guide - Parsing Date and Time

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.

• Low-Level Time String Parsing: Interpret string according to given format.
• General Time String Parsing: User-friendly function to parse data and time strings.