Guard __has_attribute for compilers that don't support it (#1129)

* Guard `__has_attribute` for compilers that don't support it Signed-off-by: Larry Gritz <lg@larrygritz.com> * Revision Signed-off-by: Larry Gritz <lg@larrygritz.com>
AcademySoftwareFoundation · Aug 18, 2021 · 957e7c6 · 957e7c6
1 parent 0cafc43
commit 957e7c6
Showing 1 changed file with 8 additions and 0 deletions.
diff --git a/cmake/OpenEXRConfig.h.in b/cmake/OpenEXRConfig.h.in
@@ -56,6 +56,14 @@
                              (uint32_t(OPENEXR_VERSION_MINOR) << 16) | \
                              (uint32_t(OPENEXR_VERSION_PATCH) <<  8))
 
+
+// On modern versions of gcc & clang, __has_attribute can test support for
+// __attribute__((attr)).  Make sure it's safe for other compilers.
+#ifndef __has_attribute
+#    define __has_attribute(x) 0
+#endif
+
+
 // Whether the user configured the library to have symbol visibility
 // tagged
 #cmakedefine OPENEXR_ENABLE_API_VISIBILITY