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-rw-r--r--m4/tls.m417
1 files changed, 17 insertions, 0 deletions
diff --git a/m4/tls.m4 b/m4/tls.m4
new file mode 100644
index 00000000..3808f06e
--- /dev/null
+++ b/m4/tls.m4
@@ -0,0 +1,17 @@
+AC_DEFUN([CC_CHECK_TLS], [
+ AC_CACHE_CHECK([whether $CC knows __thread for Thread-Local Storage],
+ cc_cv_tls___thread,
+ [AC_COMPILE_IFELSE(
+ AC_LANG_PROGRAM(
+ [[static __thread int a = 6;]],
+ [[a = 5;]]),
+ [cc_cv_tls___thread=yes],
+ [cc_cv_tls___thread=no])
+ ])
+
+ AS_IF([test "x$cc_cv_tls___thread" = "xyes"],
+ [AC_DEFINE([SUPPORT_TLS___THREAD], 1,
+ [Define this if the compiler supports __thread for Thread-Local Storage])
+ $1],
+ [$2])
+])