A Configure test for C11 thread local storage specificer, _Thread_local

We also provbe for gcc's earlier syntax, __thread.

1 files changed, 12 insertions, 0 deletions

diff --git a/config_h.SH b/config_h.SH
index 82677a4a1c..9652cad49d 100755
--- a/config_h.SH
+++ b/config_h.SH
@@ -1073,6 +1073,18 @@ sed <<!GROK!THIS! >$CONFIG_H -e 's!^#undef\(.*/\)\*!/\*#define\1 \*!' -e 's!^#un
 #$d_static_inline HAS_STATIC_INLINE				/**/
 #define PERL_STATIC_INLINE $perl_static_inline	/**/
 
+/* PERL_THREAD_LOCAL:
+ *	This symbol, if defined, gives a linkage specification for thread-local
+ *	storage. For example, for a C11 compiler this will be _Thread_local.
+ *	Beware, some compilers are sensitive to the C language standard they are
+ *	told to parse. For example, suncc defaults to C11, so our probe will
+ *	report that _Thread_local can be used. However, if the -std=c99 is later
+ *	added to the compiler flags, then _Thread_local will become a syntax
+ *	error. Hence it is important for these flags to be consistent between
+ *	probing and use.
+ */
+#$d_thread_local PERL_THREAD_LOCAL $perl_thread_local	/**/
+
 /* USE_STDIO_PTR:
  *	This symbol is defined if the _ptr and _cnt fields (or similar)
  *	of the stdio FILE structure can be used to access the stdio buffer