X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/5a5d3c080fe1675619f57e0079fc88ea917f21c5..4e3ad7c095f0a047b48445d76316fc20f394f3e9:/acinclude.m4

diff --git a/acinclude.m4 b/acinclude.m4
index c81c17bc7b..6479c8eaab 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -144,6 +144,53 @@ AC_DEFUN([WX_CPP_BOOL],
   fi
 ])
 
+dnl ---------------------------------------------------------------------------
+dnl WX_CPP_EXPLICIT checks whether the C++ compiler support the explicit
+dnl keyword and defines HAVE_EXPLICIT if this is the case
+dnl ---------------------------------------------------------------------------
+
+AC_DEFUN([WX_CPP_EXPLICIT],
+[
+  AC_CACHE_CHECK([if C++ compiler supports the explicit keyword],
+                 wx_cv_explicit,
+  [
+    AC_LANG_SAVE
+    AC_LANG_CPLUSPLUS
+
+    dnl do the test in 2 steps: first check that the compiler knows about the
+    dnl explicit keyword at all and then verify that it really honours it
+    AC_TRY_COMPILE(
+      [
+        class Foo { public: explicit Foo(int) {} };
+      ],
+      [
+        return 0;
+      ],
+      [
+        AC_TRY_COMPILE(
+            [
+                class Foo { public: explicit Foo(int) {} };
+                static void TakeFoo(const Foo& foo) { }
+            ],
+            [
+                TakeFoo(17);
+                return 0;
+            ],
+            wx_cv_explicit=no,
+            wx_cv_explicit=yes
+        )
+      ],
+      wx_cv_explicit=no
+    )
+
+    AC_LANG_RESTORE
+  ])
+
+  if test "$wx_cv_explicit" = "yes"; then
+    AC_DEFINE(HAVE_EXPLICIT)
+  fi
+])
+
 dnl ---------------------------------------------------------------------------
 dnl a slightly better AC_C_BIGENDIAN macro which allows cross-compiling
 dnl ---------------------------------------------------------------------------