1 files changed, 47 insertions, 3 deletions
diff --git a/include/ruby/internal/arithmetic/intptr_t.h b/include/ruby/internal/arithmetic/intptr_t.h
index 442c87144c..70090f88e6 100644
--- a/include/ruby/internal/arithmetic/intptr_t.h
+++ b/include/ruby/internal/arithmetic/intptr_t.h
@@ -17,7 +17,7 @@
  *             recursively included  from extension  libraries written  in C++.
  *             Do not  expect for  instance `__VA_ARGS__` is  always available.
  *             We assume C99  for ruby itself but we don't  assume languages of
- *             extension libraries. They could be written in C++98.
+ *             extension libraries.  They could be written in C++98.
  * @brief      Arithmetic conversion between C's `intptr_t` and Ruby's.
  */
 #include "ruby/internal/config.h"
@@ -29,13 +29,57 @@
 #include "ruby/internal/value.h"
 #include "ruby/internal/dllexport.h"
 
-#define rb_int_new  rb_int2inum
-#define rb_uint_new rb_uint2inum
+#define rb_int_new  rb_int2inum  /**< @alias{rb_int2inum} */
+#define rb_uint_new rb_uint2inum /**< @alias{rb_uint2inum} */
+
+// These definitions are same as fiddle/conversions.h
+#if SIZEOF_VOIDP <= SIZEOF_LONG
+# define PTR2NUM(x) (LONG2NUM((long)(x)))
+# define NUM2PTR(x) ((void*)(NUM2ULONG(x)))
+#elif SIZEOF_VOIDP <= SIZEOF_LONG_LONG
+# define PTR2NUM(x) (LL2NUM((LONG_LONG)(x)))
+# define NUM2PTR(x) ((void*)(NUM2ULL(x)))
+#else
+// should have been an error in ruby/internal/value.h
+# error Need integer for VALUE
+#endif
 
 RBIMPL_SYMBOL_EXPORT_BEGIN()
+
+/**
+ * Converts a C's `intptr_t` into an instance of ::rb_cInteger.
+ *
+ * @param[in]  i  Arbitrary `intptr_t` value.
+ * @return     An instance of ::rb_cInteger.
+ * @note       This function always allocates Bignums, even if the given number
+ *             is small enough to fit into a Fixnum.
+ */
 VALUE rb_int2big(intptr_t i);
+
+/**
+ * Converts a C's `intptr_t` into an instance of ::rb_cInteger.
+ *
+ * @param[in]  i  Arbitrary `intptr_t` value.
+ * @return     An instance of ::rb_cInteger.
+ */
 VALUE rb_int2inum(intptr_t i);
+
+/**
+ * Converts a C's `intptr_t` into an instance of ::rb_cInteger.
+ *
+ * @param[in]  i  Arbitrary `intptr_t` value.
+ * @return     An instance of ::rb_cInteger.
+ * @note       This function always allocates Bignums, even if the given number
+ *             is small enough to fit into a Fixnum.
+ */
 VALUE rb_uint2big(uintptr_t i);
+
+/**
+ * Converts a C's `uintptr_t` into an instance of ::rb_cInteger.
+ *
+ * @param[in]  i  Arbitrary `uintptr_t` value.
+ * @return     An instance of ::rb_cInteger.
+ */
 VALUE rb_uint2inum(uintptr_t i);
 RBIMPL_SYMBOL_EXPORT_END()