According to MSVC manual (*1), cl.exe can skip including a header file
when that:
- contains #pragma once, or
- starts with #ifndef, or
- starts with #if ! defined.
GCC has a similar trick (*2), but it acts more stricter (e. g. there
must be _no tokens_ outside of #ifndef...#endif).
Sun C lacked #pragma once for a looong time. Oracle Developer Studio
12.5 finally implemented it, but we cannot assume such recent version.
This changeset modifies header files so that each of them include
strictly one #ifndef...#endif. I believe this is the most portable way
to trigger compiler optimizations. [Bug #16770]
*1: https://docs.microsoft.com/en-us/cpp/preprocessor/once
*2: https://gcc.gnu.org/onlinedocs/cppinternals/Guard-Macros.html
zlib and bignum both contain unblocking functions which are
async-signal-safe and do not require spawning additional
threads.
We can execute those functions directly in signal handlers
without incurring overhead of extra threads, so provide C-API
users the ability to deal with that. Other C-API users may
have similar need.
This flexible API can supercede existing uses of
rb_thread_call_without_gvl and rb_thread_call_without_gvl2 by
introducing a flags argument to control behavior.
Note: this API is NOT finalized. It needs approval from other
committers. I prefer shorter name than previous
rb_thread_call_without_gvl* functions because my eyes requires
big fonts.
[Bug #15499]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66712 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
meaning of function.
This function is called with same parameters of
`rb_thread_call_without_gvl()'.
However, if interrupts are detected, when return immediately.
* thread.c: implement `rb_thread_call_without_gvl2()'.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37938 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
`func' from `int *skip_interrupt' to `VALUE *flags'.
If (flags & RUBY_CALL_WO_GVL_FLAG_SKIP_CHECK_INTS) is not zero,
then skip checking interrupt.
[ruby-core:46547]
* include/ruby/thread.h: ditto.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37681 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
it can skip last CHECK_INTS. See document for more details.
Document about it was updated a bit.
* include/ruby/thread.h (decl. of rb_thread_call_without_gvl2): added.
* thread.c (rb_thread_call_with_gvl): remove "EXPERIMENTAL!"
warning from a document.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36433 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
