2627. [filesys.ts] [PDTS] Return value of uintmax_t on error?

Section: 15.14 [filesys.ts::fs.op.file_size] Status: TS Submitter: FI-9 Opened: 2014-01-20 Last modified: 2017-07-30

Priority: Not Prioritized

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Discussion:

Addresses: filesys.ts

"The signature with argument ec returns static_cast<uintmax_t>(-1) if an error occurs.", one would expect that both signatures return that if an error occurs?

Clarify the Returns clause, and apply the same for every function that returns an uintmax_t where applicable.

[2014-02-13 LWG/SG-3 Issaquah:]

Discussion when around in circles for a while, until someone suggested the reference to 15.15 was wrong, and that the issue applied to the previous function in the WP, 15.14 File size [fs.op.file_size].

The NB Comment makes much more sense if it applies to file_size(), so the chair was directed to change the reference from 15.15 [fs.op.hard_lk_ct] to 15.14 [fs.op.file_size].

The intent that file_size() is only meaningful for regular_files. Beman to strike the the static_cast, changing it to "Otherwise an error is reported.".

Proposed resolution:

Change 15.14 [fs.op.file_size]:

uintmax_t file_size(const path& p);
uintmax_t file_size(const path& p, error_code& ec) noexcept;

Returns: If !exists(p) && || !is_regular_file(p) an error is reported (7). Otherwise, the size in bytes of the file p resolves to, determined as if by the value of the POSIX stat structure member st_size obtained as if by POSIX stat(). Otherwise, static_cast<uintmax_t>(-1). The signature with argument ec returns static_cast<uintmax_t>(-1) if an error occurs.

Throws: As specified in Error reporting (7).