IMATH_NOEXCEPT macro to make noexcept a compile-time option

config/ImathConfig.h.in

@@ -55,6 +55,21 @@
 // IMATH_LIB_VERSION is the library API version: SOCURRENT.SOAGE.SOREVISION
 #define IMATH_LIB_VERSION_STRING "@IMATH_LIB_VERSION@"
 
+//
+// Code that depends on the v2 ExcMath mechanism of signal handlers
+// that throw exceptions is incompatible with noexcept, since
+// floating-point overflow and underflow can occur in a wide variety
+// of computations within Imath functions now marked with
+// noexcept. Code that needs to accomodate the exception-handling
+// behavior can build with the IMATH_USE_NOEXCEPT off.
+//
+
+#cmakedefine01 IMATH_USE_NOEXCEPT
+#if IMATH_USE_NOEXCEPT
+#define IMATH_NOEXCEPT noexcept
+#else
+#define IMATH_NOEXCEPT
+#endif
 
 //
 // By default, opt into the interoparability constructors and assignments.

config/ImathSetup.cmake

@@ -17,6 +17,9 @@ option(IMATH_USE_DEFAULT_VISIBILITY "Makes the compile use default visibility (b
 # object (if you enable this) that contains a LUT of the function
 option(IMATH_ENABLE_LARGE_STACK "Enables code to take advantage of large stack support"     OFF)
 
+# Option to make it possible to build without the noexcept specifier
+option(IMATH_USE_NOEXCEPT "Compile with noexcept specifier" ON)
+
 # What C++ standard to compile for.  VFX Platform 18 is c++14, so
 # that's the default.
 set(tmp 14)

docs/Doxyfile

@@ -20,9 +20,9 @@ PREDEFINED = IMATH_CONSTEXPR14=constexpr \
              IMATH_INTERNAL_NAMESPACE_SOURCE_EXIT="}" \
              IMATH_INTERNAL_NAMESPACE_HEADER_ENTER="namespace Imath {" \
              IMATH_INTERNAL_NAMESPACE_HEADER_EXIT="}" \
+             IMATH_NOEXCEPT="noexcept" \
              IMATH_EXPORT= \
              IMATH_EXPORT_ENUM= \
              IMATH_EXPORT_TYPE= \
              IMATH_EXPORT_TEMPLATE_TYPE= \
-             __cplusplus=1 
-
+             __cplusplus=1