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Re: Don't discuss details of what type size_t might be typedefed to
Here is a new version of the size_t patch, which retains a mention of
the types size_t might be when using the GNU C Library.
2012-02-28 Joseph Myers <joseph@codesourcery.com>
* manual/lang.texi (size_t): Note types to which size_t may be
equivalent with the GNU C Library, but do not describe when
differences between them are significant.
diff --git a/manual/lang.texi b/manual/lang.texi
index 2a73c72..6cb7371 100644
--- a/manual/lang.texi
+++ b/manual/lang.texi
@@ -629,27 +629,13 @@ This is an unsigned integer type used to represent the sizes of objects.
The result of the @code{sizeof} operator is of this type, and functions
such as @code{malloc} (@pxref{Unconstrained Allocation}) and
@code{memcpy} (@pxref{Copying and Concatenation}) accept arguments of
-this type to specify object sizes.
+this type to specify object sizes. On systems using @theglibc{}, this
+will be @w{@code{unsigned int}} or @w{@code{unsigned long int}}.
@strong{Usage Note:} @code{size_t} is the preferred way to declare any
arguments or variables that hold the size of an object.
@end deftp
-In the GNU system @code{size_t} is equivalent to either
-@w{@code{unsigned int}} or @w{@code{unsigned long int}}. These types
-have identical properties on the GNU system and, for most purposes, you
-can use them interchangeably. However, they are distinct as data types,
-which makes a difference in certain contexts.
-
-For example, when you specify the type of a function argument in a
-function prototype, it makes a difference which one you use. If the
-system header files declare @code{malloc} with an argument of type
-@code{size_t} and you declare @code{malloc} with an argument of type
-@code{unsigned int}, you will get a compilation error if @code{size_t}
-happens to be @code{unsigned long int} on your system. To avoid any
-possibility of error, when a function argument or value is supposed to
-have type @code{size_t}, never declare its type in any other way.
-
@strong{Compatibility Note:} Implementations of C before the advent of
@w{ISO C} generally used @code{unsigned int} for representing object sizes
and @code{int} for pointer subtraction results. They did not
--
Joseph S. Myers
joseph@codesourcery.com