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| author | Nicholas Clark <nick@ccl4.org> | 2022-01-04 18:27:17 +0000 |
|---|---|---|
| committer | Nicholas Clark <nick@ccl4.org> | 2022-01-12 20:12:50 +0000 |
| commit | c4b6855dd57cd9a2ac4647c33c5636ed7d15d64a (patch) | |
| tree | 03836a092e02ec90439d106e93ea40179629cacb /thread.h | |
| parent | 79314061206e91d12ed1d2ee0915c80b7375f8b8 (diff) | |
| download | perl-c4b6855dd57cd9a2ac4647c33c5636ed7d15d64a.tar.gz | |
For C++ extensions, use the pthreads definition of PERL_GET_CONTEXT
Configure probes the C compiler to find out whether it supports C11 thread
local storage, and if found uses this for PERL_SET_CONTEXT/PERL_GET_CONTEXT,
in preference to the pthread_setspecific()/pthread_getspecific() approach.
However, we can come unstuck with XS extensions written in C++, as C++ and C
disagree on the syntax used for thread local storage, meaning that the
working token that Configure probed for C turns out to be a compiler error
on C++.
As Configure doesn't have a way to probe for C++ dialects, we just take the
safe option and do the same as 5.34.0 and earlier - use pthreads on C++.
This commit is minimal because the implementation of PERL_SET_CONTEXT for
C11 thread local storage was already defensively written to *also* call
pthread_setspecific().
Diffstat (limited to 'thread.h')
| -rw-r--r-- | thread.h | 12 |
1 files changed, 10 insertions, 2 deletions
@@ -372,8 +372,16 @@ # define PTHREAD_GETSPECIFIC(key) pthread_getspecific(key) #endif -#if defined(PERL_THREAD_LOCAL) && !defined(PERL_GET_CONTEXT) && !defined(PERL_SET_CONTEXT) -/* Use C11 thread-local storage, where possible: */ +#if defined(PERL_THREAD_LOCAL) && !defined(PERL_GET_CONTEXT) && !defined(PERL_SET_CONTEXT) && !defined(__cplusplus) +/* Use C11 thread-local storage, where possible. + * Frustratingly we can't use it for C++ extensions, C++ and C disagree on the + * syntax used for thread local storage, meaning that the working token that + * Configure probed for C turns out to be a compiler error on C++. Great. + * (Well, unless one or both is supporting non-standard syntax as an extension) + * As Configure doesn't have a way to probe for C++ dialects, we just take the + * safe option and do the same as 5.34.0 and earlier - use pthreads on C++. + * Of course, if C++ XS extensions really want to avoid *all* this overhead, + * they should #define PERL_NO_GET_CONTEXT and pass aTHX/aTHX_ explicitly) */ # define PERL_USE_THREAD_LOCAL extern PERL_THREAD_LOCAL void *PL_current_context; |