Address default value blob review feedback

Author: duckdoom5

include/slang-deprecated.h

@@ -710,14 +710,30 @@ extern "C"
         SlangReflectionVariable* var,
         SlangSession* globalSession,
         char const* name);
-    /** DEPRECATED: use `spReflectionVariable_GetDefaultValueBlob` instead. */
+    /** DEPRECATED: use `spReflectionVariable_GetDefaultValueBlob` and check for a null blob
+     * instead. */
     SLANG_API bool spReflectionVariable_HasDefaultValue(SlangReflectionVariable* inVar);
     /** DEPRECATED: use `spReflectionVariable_GetDefaultValueBlob` instead. */
     SLANG_API SlangResult
     spReflectionVariable_GetDefaultValueInt(SlangReflectionVariable* inVar, int64_t* rs);
     /** DEPRECATED: use `spReflectionVariable_GetDefaultValueBlob` instead. */
     SLANG_API SlangResult
     spReflectionVariable_GetDefaultValueFloat(SlangReflectionVariable* inVar, float* rs);
+    /** Retrieves a variable's default initializer as a blob.
+     *
+     * If no explicit initializer exists, returns `SLANG_OK` and sets `*outBlob` to `nullptr`.
+     * On success with an initializer, `*outBlob` receives an `ISlangBlob*` with an added
+     * reference.
+     *
+     * Supported types include scalar values, vectors, matrices, fixed-size arrays,
+     * structs/aggregates, and enums. The blob stores scalar-layout bytes in natural scalar/field
+     * order without aggregate padding; bool values are emitted as 4-byte values to match Slang's
+     * GPU scalar layout. Matrices are emitted row-by-row, struct base fields are emitted before
+     * derived fields, and enum values use the enum's underlying tag type.
+     *
+     * Returns `SLANG_E_INVALID_ARG` for invalid arguments and `SLANG_E_NOT_AVAILABLE` when the
+     * initializer cannot be represented as a default-value blob.
+     */
     SLANG_API SlangResult
     spReflectionVariable_GetDefaultValueBlob(SlangReflectionVariable* inVar, ISlangBlob** outBlob);
     SLANG_API SlangReflectionGeneric* spReflectionVariable_GetGenericContainer(

include/slang.h

@@ -3113,7 +3113,7 @@ struct VariableReflection
         return findAttributeByName(globalSession, name);
     }
 
-    /// Deprecated: use getDefaultValueBlob instead.
+    /// Deprecated: call getDefaultValueBlob and check for a null blob instead.
     SLANG_DEPRECATED bool hasDefaultValue()
     {
         return spReflectionVariable_HasDefaultValue((SlangReflectionVariable*)this);
@@ -3137,10 +3137,19 @@ struct VariableReflection
         return spReflectionVariable_GetDefaultValueFloat((SlangReflectionVariable*)this, value);
     }
 
-    /// Gets default value bytes for scalar and aggregate variables with explicit initializers.
-    /// If the variable has no explicit initializer, this succeeds with a null blob.
-    /// The returned blob stores values in natural scalar/field order, without constant-buffer
-    /// padding.
+    /// Gets default initializer bytes for variables with representable initializers.
+    ///
+    /// If the variable has no explicit initializer, this succeeds with a null blob. On success with
+    /// an initializer, `outBlob` receives an `ISlangBlob*` with an added reference.
+    ///
+    /// Supported types include scalar values, vectors, matrices, fixed-size arrays,
+    /// structs/aggregates, and enums. The returned blob stores scalar-layout bytes in natural
+    /// scalar/field order without aggregate padding; bool values are emitted as 4-byte values to
+    /// match Slang's GPU scalar layout. Matrices are emitted row-by-row, struct base fields are
+    /// emitted before derived fields, and enum values use the enum's underlying tag type.
+    ///
+    /// Returns SLANG_E_INVALID_ARG for invalid arguments and SLANG_E_NOT_AVAILABLE when an
+    /// initializer cannot be represented as a default-value blob.
     SlangResult getDefaultValueBlob(ISlangBlob** outBlob)
     {
         return spReflectionVariable_GetDefaultValueBlob((SlangReflectionVariable*)this, outBlob);