diff options
Diffstat (limited to 'contrib/gcc/doc/extend.texi')
| -rw-r--r-- | contrib/gcc/doc/extend.texi | 41 |
1 files changed, 38 insertions, 3 deletions
diff --git a/contrib/gcc/doc/extend.texi b/contrib/gcc/doc/extend.texi index db6f1bd..caf0be0 100644 --- a/contrib/gcc/doc/extend.texi +++ b/contrib/gcc/doc/extend.texi @@ -85,6 +85,8 @@ extensions, accepted by GCC in C89 mode and in C++. * Unnamed Fields:: Unnamed struct/union fields within structs/unions. * Thread-Local:: Per-thread variables. * Binary constants:: Binary constants using the @samp{0b} prefix. +@c APPLE LOCAL blocks 7205047 5811887 +* Blocks:: Anonymous functions (closures). @end menu @node Statement Exprs @@ -378,9 +380,14 @@ allows the data to be read-only. @cindex thunks A @dfn{nested function} is a function defined inside another function. -(Nested functions are not supported for GNU C++.) The nested function's -name is local to the block where it is defined. For example, here we -define a nested function named @code{square}, and call it twice: +@c APPLE LOCAL begin nested functions 4357979 +Nested functions are not supported for GNU C++ and are disable by +default on FreeBSD. The @option{-fnested-functions} and +@option{-fno-nested-functions} options can be used to enable and +disable nested function suppport. The nested function's name is local +to the block where it is defined. For example, here we define a +nested function named @code{square}, and call it twice: +@c APPLE LOCAL end nested functions 4357979 @smallexample @group @@ -3786,6 +3793,22 @@ and caught in another, the class must have default visibility. Otherwise the two shared objects will be unable to use the same typeinfo node and exception handling will break. +@c APPLE LOCAL begin weak types 5954418 +@item weak +In C++, attribute weak can be applied to a class to ensure that all +non-hidden instances of the type are treated as the same type across +shared library boundaries on platforms (such as darwin and arm aapcs) +that can emit vtables and the type info meta data as non-comdat +symbols. This is useful when the class has a key method and the +translation unit that contains the key method is used in more than one +shared library or in a shared library and the application. Doing this +results in more expensive startup times. This attribute is inherited +by subclasses, so it is only necessary to mark a base type. The +typical use would be to mark any types used for throwing across shared +library boundaries or those used in dynamic_cast operations across a +shared library boundary. +@c APPLE LOCAL end weak types 5954418 + @subsection ARM Type Attributes On those ARM targets that support @code{dllimport} (such as Symbian @@ -10534,6 +10557,18 @@ Non-@code{static} members shall not be @code{__thread}. @end quotation @end itemize +@c APPLE LOCAL begin blocks 7205047 5811887 +@node Blocks +@section Blocks +@cindex Blocks +@cindex __block + +Blocks is a language feature that allows one to create anonymous +functions. The feature is also known as lambdas or closures in other +languages. The feature is controlled by @option{-fblocks}. +See @uref{http://developer.apple.com/mac/library/documentation/Cocoa/Conceptual/Blocks/Articles/00_Introduction.html} for additional details. +@c APPLE LOCAL end blocks 7205047 5811887 + @node Binary constants @section Binary constants using the @samp{0b} prefix @cindex Binary constants using the @samp{0b} prefix |
