[libc-commits] [PATCH] D98467: This introduces gmtime to LLVM libc, based on C99/C2X/Single Unix Spec.

[Jeff Bailey via Phabricator via libc-commits]

jeffbailey added inline comments.


================
Comment at: libc/src/time/gmtime.cpp:18
+LLVM_LIBC_FUNCTION(struct tm *, gmtime, (const time_t *timer)) {
+  // TODO(rtenneti): This method is not thread safe.
+  static struct tm tm_out;
----------------
sivachandra wrote:
> Does any standard require thread safety? If yes, will making the below declaration thread-local solve the problem?
C20 introduces gmtime_r (and the family of _r time functions).

In 7.27.3:

" Execution of any of the functions that return a pointer to one of these static
objects may overwrite the information returned from any previous call to one of these functions that
uses the same object. "

But what's not clear to me is for the non-reentrant versions, is doing a thread-local OK? I'm not seeing anything in the standard discussing static buffers and the use of thread-locals to store them (it only's mentioned in the definition of errno)



Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D98467/new/

https://reviews.llvm.org/D98467