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### 3245. Unnecessary restriction on `'%p'` parse specifier

Section: 27.13 [time.parse] Status: C++20 Submitter: Tomasz Kamiński Opened: 2019-07-31 Last modified: 2021-02-25

Priority: 0

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Discussion:

The current specification for the `'%p'` flag in "[tab:time.parse.spec] Meaning of `parse` flags" places a restriction of it's placement with regards to the `'%I'` command:

> The locale's equivalent of the AM/PM designations associated with a 12-hour clock. The command `%I` must precede `%p` in the format string.

This restriction makes the migration to new API more difficult, as it is not present for the POSIX `strptime` nor in the example implementation of the library. Per Howard's comment:

> Actually this is an obsolete requirement and it should be struck. The first time I implemented this I didn't know how to do it without this requirement. I've since reimplemented it without needing this.

[2019-08-17 Issue Prioritization]

Status to Tentatively Ready and priority to 0 after eight positive votes on the reflector.

Proposed resolution:

This wording is relative to N4830.

1. Modify Table 99 "Meaning of `parse` flags [tab:time.parse.spec]" in 27.13 [time.parse] as indicated:

   > Table 99: Meaning of `parse` flags [tab:time.parse.spec]
   > Flag | Parsed value
   > --- | ---
   > `[…]`
   > `%p` | The locale's equivalent of the AM/PM designations associated with a 12-hour clock. The command `%I` must precede `%p` in the format string.
   > `[…]`