Re: doc: Mention a gmtime_r problem

[Eric Blake]

On Tue, Sep 03, 2024 at 11:34:27AM GMT, Bruno Haible wrote:
> POSIX specifies that gmtime_r sets the tm_zone field to "UTC". (Interestingly,
> no such requirement exists for gmtime.)

But see https://austingroupbugs.net/view.php?id=1797#c6794; the Austin
Group is trying to work with the C committee to get this fixed in the
future (with Paul's help); among other things, it fixes gmtime() and
gmtime_r() to both have to set a value of either "GMT" or "UTC":

| On page 1211 line 41381 section gmtime() DESCRIPTION, change (already in CX 
shading):
| 
| 
|     ...where the names in the structure and in the expression correspond.
| 
| 
| to:
| 
| 
|     ...where the names in the structure and in the expression
| correspond; additionally, the tm_gmtoff field of the struct tm shall
| be set to 0, and the tm_zone field shall be set to a pointer to an
| implementation-defined string set to "UTC" or "GMT", which shall
| have static storage duration.


-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.
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