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| author | William R. Otte <wotte@dre.vanderbilt.edu> | 2008-03-04 13:56:48 +0000 |
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| committer | William R. Otte <wotte@dre.vanderbilt.edu> | 2008-03-04 13:56:48 +0000 |
| commit | c4078c377d74290ebe4e66da0b4975da91732376 (patch) | |
| tree | 1816ef391e42a07929304908ac0e21f4c2f6cb7b /ACE/docs/Symbol_Versioning.html | |
| parent | 700d1c1a6be348c6c70a2085e559baeb8f4a62ea (diff) | |
| download | ATCD-c4078c377d74290ebe4e66da0b4975da91732376.tar.gz | |
swap in externals for ACE and TAO
Diffstat (limited to 'ACE/docs/Symbol_Versioning.html')
| -rw-r--r-- | ACE/docs/Symbol_Versioning.html | 233 |
1 files changed, 0 insertions, 233 deletions
diff --git a/ACE/docs/Symbol_Versioning.html b/ACE/docs/Symbol_Versioning.html deleted file mode 100644 index d0d50bca914..00000000000 --- a/ACE/docs/Symbol_Versioning.html +++ /dev/null @@ -1,233 +0,0 @@ -<!-- $Id$ --> - -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> -<html> - <head> - <title>Symbol Versioning in ACE</title> - </head> - - <body> - <h3>Symbol Versioning in ACE</h3> - - <p> - To provide a means for ACE-based application developers to avoid - symbol conflicts when multiple versions of ACE are linked to an - application ACE supports <em>versioned namespaces</em>. When - enabled (disabled by default), ACE's versioned namespace support - causes all ACE symbols (classes, free functions, etc) to be - placed within a C++ namespace of the form "<code>namespace - ACE_5_5_1</code>". For example, the <code>ACE_Reactor</code> - would end up being placed in the versioned namespace like so: - </p> - - <blockquote> - <code> -<pre> - namespace ACE_5_5_1 - { - class ACE_Reactor - { - ... - }; - } - using namespace ACE_5_5_1; -</pre> - </code> - </blockquote> - - <p> - Notice that a <code>using</code> clause exposes the ACE types - embedded in the versioned namespace back to the global - namespace. This maximizes source code compatibility. ACE - itself does this through the use of two macros: - </p> - <ul> - <li> - <code>ACE_BEGIN_VERSIONED_NAMESPACE_DECL</code><br> - <ul> - <li> - Expands to "<code>namespace ACE_VERSIONED_NAMESPACE NAME - {</code>", where - <code>ACE_VERSIONED_NAMESPACE_NAME</code> by defaults to - namespace name of the form - <code>ACE_<em>major</em>_<em>minor</em>_<em>beta</em></code>. - Users may override the default by defining the - <code>ACE_VERSIONED_NAMESPACE_NAME</code> preprocessor - symbol in their <code><strong>ace/config.h</strong></code> - header file. - </li> - </ul> - </li> - <li> - <code>ACE_END_VERSIONED_NAMESPACE_DECL</code> - <ul> - <li> - Expands to "<code>} using namespace - ACE_VERSIONED_NAMESPACE_NAME;</code>", where - <code>ACE_VERSIONED_NAMESPACE_NAME</code> is described - above. - </li> - </ul> - </li> - </ul> - <h2>Things ACE-based Application Developers Should Know</h2> - <p> - Every effort has been made to make the versioned namespace - support in ACE as transparent as possible, including transparent - versioned symbol support in the ACE_Service_Configurator when - the ACE_Service_Configurator macros, such as <em>e.g.</em>, - <code>ACE_FACTORY_DECLARE</code>, are used appropriately. No - changes to service configurator directives are necessary. For - example, the <code>ACE_Service_Configurator</code> will - transparently mangle the factory function name in a service - configurator directive on-the-fly, meaning it will only load a - "versioned" factory function name. This allows multiple service - object factory functions, for example, to coexist in the same - process space. - </p> - <p> - There is, however, at least one caveat with respect to source - code compatibility: any forward declarations of ACE symbols must - also be placed within the versioned namespace. For example, if - you have a forward declaration for <code>ACE_Reactor</code> in - your application code, you will need to place it within the - configured ACE versioned namespace as follows: - </p> - <blockquote> - <code> -<pre> - ACE_BEGIN_VERSIONED_NAMESPACE_DECL - class ACE_Reactor; - ACE_END_VERSIONED_NAMESPACE_DECL -</pre> - </code> - </blockquote> - <p> - This must only be done once, as these macros hide the versioned - namespace name details from the application. Alternatively, you - could place the forward declaration in a namespace that is an - alias of the ACE versioned namespace, <em>e.g.</em>: - </p> - <blockquote> - <code> -<pre> - namespace Foo = ACE_VERSIONED_NAMESPACE_NAME;</code> - namespace Foo { - class ACE_Reactor; - } - using namespace Foo; -</pre> - </code> - </blockquote> - <p> - Versioned namespace support in ACE may be enabled by adding - <code>versioned_namespace=1</code> to your MPC - <code><strong>default.features</strong></code> file. - </p> - - <h2>Things ACE Developers Should Know</h2> - <p> - ACE developers should place all ACE symbols that are potentially - exposed to the user, including forward declarations in a - versioned namespace using the - <code>ACE_BEGIN_VERSIONED_NAMESSPACE_DECL</code> and - <code>ACE_END_VERSIONED_NAMESPACE_DECL</code> macros. Free - functions that are declared to have a C calling convention - (<em>i.e.</em>, <code>extern "C"</code>) should have their names - mangled using the <code>ACE_PREPROC_CONCATENATE</code> - preprocessor. For example: - </p> - <blockquote> - <code> -<pre> - void ACE_func (void) { ... } - ... - ACE_func(); // Call ACE_func() -</pre> - </code> - </blockquote> - <p> - becomes: - </p> - <blockquote> - <code> -<pre> - #if (defined (ACE_HAS_VERSIONED_NAMESPACE) \ - && ACE_HAS_VERSIONED_NAMESPACE == 1) \ - && !(defined (_MSC_VER) && _MSC_VER <= 1200) - // MSVC++ 6's preprocessor can't handle macro expansions - // required by the versioned namespace support. *sigh* - - # define ACE_FOO_FUNC_NAME ACE_PREPROC_CONCATENATE(ACE_VERSIONED_NAMESPACE_NAME, _ACE_foo_func) - - #else - - # define ACE_FOO_FUNC_NAME ACE_foo_func - - #endif /* ACE_HAS_VERSIONED_NAMESPACE == 1 */ - - ... - void ACE_FOO_FUNC_NAME (void) { ... } - - ACE_FOO_FUNC_NAME(); // Call mangled ACE_foo_func(). -</pre> - </code> - </blockquote> - <p> - The <code>ACE_PREPROC_CONCATENATE</code> is used rather than a - straight <code>##</code> preprocessor concatenation since in the - latter case preprocessor symbols like - <code>ACE_VERSIONED_NAMESPACE_NAME</code> will not be expanded - if they are concatenated. <code>ACE_PREPROCE_CONCATENATE</code> - forces the preprocessor to expand them during the argument - prescan by calling a macro that itself calls another that - performs the actual concatenation. - </p> - <h3>General Guidelines</h3> - <ul> - <li> - Versioned namespace macro/support must be added to all new files - added to ACE. - </li> - <li> - Do not place include directives between - <code>ACE_BEGIN_VERSIONED_NAMESPACE_DECL</code> and - <code>ACE_END_VERSIONED_NAMESPACE_DECL</code> macros. Doing - so will cause nested namespace to be created, which is not - the desired affect. - </li> - <li>Be aware of preprocessor conditional blocks when placing the - versioned namespace macros. For example, if you open - versioned namespace within a given preprocessor condition - block, you'll most likely want to close it in the same - block. - </li> - <li> - If necessary, reopen and close the versioned namespace - multiple times in the same file by using the macros multiple - times to address the concerns described in the above two - items. - </li> - <li> - The <code>$ACE_ROOT/bin/fuzz.pl</code> script has a sanity - checking test for versioned namespaces that may be of use when - debugging nested namespace issues, and for detecting - <code>BEGIN</code>/<code>END</code> mismatches. - </li> - </ul> - <p> - Versioned namespace support in ACE may be enabled by adding - <code>versioned_namespace=1</code> to your MPC - <code><strong>default.features</strong></code> file. Additional -information about versioned namespaces is available from the <A -HREF="http://www.riverace.com/newsletters/March2006.htm">Riverace -website</A>. - </p> - <hr> - <address><a href="mailto:ossama@dre.vanderbilt.edu">Ossama Othman</a></address> -<!-- Created: Fri Mar 17 08:35:50 PST 2006 --> -<!-- hhmts start --> -Last modified: Fri Mar 17 20:47:41 PST 2006 -<!-- hhmts end --> - </body> -</html> |