abi.html: Document effect of -fabi-version on value of __GXX_ABI_VERSION...
2004-05-13 Jonathan Wakely <redi@gcc.gnu.org> * docs/html/abi.html: Document effect of -fabi-version on value of __GXX_ABI_VERSION, and that it's defined in c-cppbuiltin.c. Fix markup. From-SVN: r81794
This commit is contained in:
Jonathan Wakely
parent
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@ -1,3 +1,9 @@
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2004-05-13 Jonathan Wakely <redi@gcc.gnu.org>
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* docs/html/abi.html: Document effect of -fabi-version on value
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of __GXX_ABI_VERSION, and that it's defined in c-cppbuiltin.c.
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Fix markup.
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2004-05-13 Benjamin Kosnik <bkoz@redhat.com>
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PR libstdc++/15074
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@ -32,7 +32,7 @@
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<!-- ####################################################### -->
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<hr />
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<h3 class="left">
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<a name="C++interface">The C++ interface</a>
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<a name="CXXinterface">The C++ interface</a>
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</h3>
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<p> C++ applications often dependent on specific language support
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@ -101,7 +101,7 @@ given compiler ABI. In a nutshell:
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</p>
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<h3 class="left">
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<a name="ABI versioning">Versioning</a>
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<a name="ABI_versioning">Versioning</a>
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</h3>
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<p> The C++ interface has evolved throughout the history of the GNU
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@ -170,8 +170,8 @@ on ELF systems).</p>
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<li>gcc-3.3.3: libgcc_s.so.1</li>
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<li>gcc-3.4.0: libgcc_s.so.1</li>
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</ul>
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</li>
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<p></p>
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</li>
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<li>Release versioning on the libstdc++.so binary, implemented in the same was as the libgcc_s.so binary, above.
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@ -195,8 +195,8 @@ on ELF systems).</p>
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<li>gcc-3.3.3: libstdc++.so.5.0.5</li>
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<li>gcc-3.4.0: libstdc++.so.6.0.0</li>
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</ul>
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</li>
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<p></p>
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</li>
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<li>Symbol versioning on the libgcc_s.so binary.
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<p>mapfile: gcc/libgcc-std.ver</p>
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@ -220,8 +220,8 @@ on ELF systems).</p>
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<li>gcc-3.3.3: GCC_3.0</li>
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<li>gcc-3.4.0: GCC_3.0</li>
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</ul>
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</li>
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<p></p>
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</li>
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<li>Symbol versioning on the libstdc++.so binary.
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@ -254,8 +254,8 @@ on ELF systems).</p>
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<li>gcc-3.3.3: GLIBCPP_3.2.3, CXXABI_1.2.1</li>
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<li>gcc-3.4.0: GLIBCXX_3.4, CXXABI_1.3</li>
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</ul>
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</li>
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<p></p>
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</li>
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<li>
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<p>Incremental bumping of a compiler pre-defined macro,
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@ -266,22 +266,26 @@ on ELF systems).</p>
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</p>
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<p>
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This macro is defined in the file "lang-specs.h" in the gcc/cp directory.
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Later versions define it in "c-common.c" in the gcc directory.
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This macro was defined in the file "lang-specs.h" in the gcc/cp directory.
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Later versions defined it in "c-common.c" in the gcc directory, and from
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G++ 3.4 it is defined in c-cppbuiltin.c and its value determined by the
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'-fabi-version' command line option.
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</p>
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<p>
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It is versioned as follows:
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It is versioned as follows, where 'n' is given by '-fabi-version=n':
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</p>
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<ul>
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<li>gcc-3.0.x: 100</li>
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<li>gcc-3.1.x: 100 (Error, should be 101)</li>
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<li>gcc-3.2.x: 102</li>
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<li>gcc-3.3.x: 102</li>
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<li>gcc-3.4.x: 1002</li>
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<li>gcc-3.4.x: 102 (when n=1)</li>
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<li>gcc-3.4.x: 1000+n (when n>1)</li>
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<li>gcc-3.4.x: 999999 (when n=0)</li>
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</ul>
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</li>
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<p></p>
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</li>
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<li>
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<p>Changes to the default compiler option for
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@ -297,8 +301,8 @@ on ELF systems).</p>
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<li>gcc-3.3.x: <code>-fabi-version=1</code></li>
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<li>gcc-3.4.x: <code>-fabi-version=2</code></li>
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</ul>
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</li>
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<p></p>
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</li>
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<li>
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<p>Incremental bumping of a library pre-defined macro. For releases
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@ -335,8 +339,8 @@ on ELF systems).</p>
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<li>gcc-3.3.3: 20040214</li>
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<li>gcc-3.4.0: 20040419</li>
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</ul>
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</li>
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<p></p>
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</li>
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<li>
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@ -344,7 +348,8 @@ on ELF systems).</p>
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Incremental bumping of a library pre-defined macro,
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_GLIBCPP_VERSION. This macro is defined as the released version of
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the library, as a string literal. This is only implemented in
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gcc-3.1.0 releases and higher, and is deprecated in 3.4.
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gcc-3.1.0 releases and higher, and is deprecated in 3.4 (where it
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is called _GLIBCXX_VERSION).
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</p>
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<p>
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@ -375,8 +380,8 @@ on ELF systems).</p>
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<li>gcc-3.3.3: "3.3.3"</li>
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<li>gcc-3.4.0: "version-unused"</li>
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</ul>
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</li>
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<p></p>
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</li>
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<li>
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<p>
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@ -389,7 +394,7 @@ on ELF systems).</p>
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directory hierarchy corresponding to the C++ compiler's released
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version. This version corresponds to the variable "gcc_version" in
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"libstdc++-v3/acinclude.m4," and more details can be found in that
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file's macro GLIBCPP_CONFIGURE.
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file's macro GLIBCXX_CONFIGURE (GLIBCPP_CONFIGURE before gcc-3.4.0).
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</p>
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<p>
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C++ includes are versioned as follows:
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@ -412,8 +417,8 @@ on ELF systems).</p>
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<li>gcc-3.3.3: include/c++/3.3.3</li>
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<li>gcc-3.4.0: include/c++/3.4.0</li>
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</ul>
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</li>
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<p></p>
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</li>
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</ul>
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<p>
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Taken together, these techniques can accurately specify interface
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@ -457,7 +462,7 @@ on ELF systems).</p>
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impact versioning and compatibility.
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</p>
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</p>
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<p>
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For more information on configure options, including ABI impacts, see:
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http://gcc.gnu.org/onlinedocs/libstdc++/configopts.html
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</p>
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@ -507,11 +512,11 @@ int main()
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%g++ hello.cc -o hello.out
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%ldd hello.out
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libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x00764000)
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libm.so.6 => /lib/tls/libm.so.6 (0x004a8000)
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libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x40016000)
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libc.so.6 => /lib/tls/libc.so.6 (0x0036d000)
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/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000)
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libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x00764000)
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libm.so.6 => /lib/tls/libm.so.6 (0x004a8000)
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libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x40016000)
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libc.so.6 => /lib/tls/libc.so.6 (0x0036d000)
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/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000)
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%nm hello.out
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</pre>
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@ -524,7 +529,7 @@ of the name, then the executable is versioned. Here's an example:
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<code> U _ZNSt8ios_base4InitC1Ev@@GLIBCXX_3.4 </code>
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<h3 class="left">
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<a name="ABI allowed">Library allowed ABI changes</a>
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<a name="ABI_allowed">Library allowed ABI changes</a>
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</h3>
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<p>
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The following will cause the library minor version number to
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@ -543,7 +548,7 @@ Other allowed changes are possible.
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<h3 class="left">
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<a name="ABI disallowed">Library disallowed ABI changes</a>
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<a name="ABI_disallowed">Library disallowed ABI changes</a>
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</h3>
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<p>
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@ -574,24 +579,24 @@ number to increase, say from "libstdc++.so.3.0.4" to
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</h3>
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<ul>
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<li>Separation of interface and implementation</li>
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<li>Separation of interface and implementation
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<p>This is accomplished by two techniques that separate the API from
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the ABI: forcing undefined references to link against a library binary
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for definitions.
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</p>
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<ul>
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<li>Include files have declarations, source files have defines</li>
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<dl>
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<dt>Include files have declarations, source files have defines</dt>
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<p> For non-templatized types, such as much of <code>class
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<dd> For non-templatized types, such as much of <code>class
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locale</code>, the appropriate standard C++ include, say
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<code>locale</code>, can contain full declarations, while various
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source files (say <code> locale.cc, locale_init.cc,
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localename.cc</code>) contain definitions.</p>
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localename.cc</code>) contain definitions.</dd>
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<li>Extern template on required types</li>
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<dt>Extern template on required types</dt>
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<p>For parts of the standard that have an explicit list of required
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<dd>For parts of the standard that have an explicit list of required
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instantiations, the GNU extension syntax <code> extern template
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</code> can be used to control where template definitions
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reside. By marking required instantiations as <code> extern
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@ -601,14 +606,15 @@ localename.cc</code>) contain definitions.</p>
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on parts of the standard that require <code> char</code> and <code>
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wchar_t</code> instantiations, and includes <code>
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basic_string</code>, the locale facets, and the types in <code>
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iostreams</code>.</p>
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iostreams</code>.</dd>
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</ul>
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</dl>
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<p> In addition, these techniques have the additional benefit that
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they reduce binary size, which can increase runtime performance.
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</p>
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</li>
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<li>Namespaces linking symbol definitions to export mapfiles</li>
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<li>Namespaces linking symbol definitions to export mapfiles
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<p>All symbols in the shared library binary are processed by a linker
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script at build time that either allows or disallows external
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@ -623,34 +629,37 @@ impacting ABI compatibility.
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<p>The following namespaces are transformed by the mapfile:</p>
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<ul>
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<li><code>namespace std</code></li>
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<p> Defaults to exporting all symbols in label
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<dl>
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<dt><code>namespace std</code></dt>
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<dd> Defaults to exporting all symbols in label
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<code>GLIBCXX</code> that do not begin with an underscore, ie
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<code>__test_func</code> would not be exported by default. Select
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exceptional symbols are allowed to be visible.</p>
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exceptional symbols are allowed to be visible.</dd>
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<li><code>namespace __gnu_cxx</code></li>
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<p> Defaults to not exporting any symbols in label
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<code>GLIBCXX</code>, select items are allowed to be visible.</p>
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<dt><code>namespace __gnu_cxx</code></dt>
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<dd> Defaults to not exporting any symbols in label
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<code>GLIBCXX</code>, select items are allowed to be visible.</dd>
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<li><code>namespace __gnu_internal</code></li>
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<p> Defaults to not exported, no items are allowed to be visible.</p>
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<dt><code>namespace __gnu_internal</code></dt>
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<dd> Defaults to not exported, no items are allowed to be visible.</dd>
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<li><code>namespace __cxxabiv1</code>, aliased to <code> namespace abi</code></li>
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<p> Defaults to not exporting any symbols in label
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<code>CXXABI</code>, select items are allowed to be visible.</p>
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</ul>
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<dt><code>namespace __cxxabiv1</code>, aliased to <code> namespace abi</code></dt>
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<dd> Defaults to not exporting any symbols in label
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<code>CXXABI</code>, select items are allowed to be visible.</dd>
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</dl>
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<p>
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</p>
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</li>
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<li>Freezing the API</li>
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<li>Freezing the API
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<p>Disallowed changes, as above, are not made on a stable release
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branch. Enforcement tends to be less strict with GNU extensions that
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standard includes.</p> </ul>
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standard includes.</p>
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</li>
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</ul>
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<h3 class="left">
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<a name="ABI testing">Testing ABI changes</a>
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<a name="ABI_testing">Testing ABI changes</a>
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</h3>
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<p>
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@ -743,7 +752,7 @@ us. We'd like to know about them!
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</p>
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<h3 class="left">
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<a name="ABI multi testing">Testing Multi-ABI binaries</a>
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<a name="ABI_multi_testing">Testing Multi-ABI binaries</a>
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</h3>
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<p>
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@ -784,18 +793,18 @@ exceptions, locale, etc.
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<p> ...with the resulting libraries looking like </p>
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<pre>
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%ldd libone.so.1.0.0
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libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x40016000)
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libm.so.6 => /lib/tls/libm.so.6 (0x400fa000)
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libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x4011c000)
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libc.so.6 => /lib/tls/libc.so.6 (0x40125000)
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/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000)
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libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x40016000)
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libm.so.6 => /lib/tls/libm.so.6 (0x400fa000)
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libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x4011c000)
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libc.so.6 => /lib/tls/libc.so.6 (0x40125000)
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/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000)
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%ldd libtwo.so.1.0.0
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libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x40027000)
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libm.so.6 => /lib/tls/libm.so.6 (0x400e1000)
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libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x40103000)
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libc.so.6 => /lib/tls/libc.so.6 (0x4010c000)
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/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000)
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libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x40027000)
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libm.so.6 => /lib/tls/libm.so.6 (0x400e1000)
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libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x40103000)
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libc.so.6 => /lib/tls/libc.so.6 (0x4010c000)
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/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000)
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</pre>
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@ -810,12 +819,12 @@ Which gives the expected:
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</p>
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<pre>
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%ldd a.out
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libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x00764000)
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libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x40015000)
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libc.so.6 => /lib/tls/libc.so.6 (0x0036d000)
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libm.so.6 => /lib/tls/libm.so.6 (0x004a8000)
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libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x400e5000)
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/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000)
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libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x00764000)
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libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0x40015000)
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libc.so.6 => /lib/tls/libc.so.6 (0x0036d000)
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libm.so.6 => /lib/tls/libm.so.6 (0x004a8000)
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libgcc_s.so.1 => /mnt/hd/bld/gcc/gcc/libgcc_s.so.1 (0x400e5000)
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/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x00355000)
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</pre>
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<p>
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@ -830,28 +839,42 @@ dependent libstdc++.so.5.
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<p>
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ABIcheck, a vague idea of checking ABI compatibility
|
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http://abicheck.sourceforge.net/
|
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<br />
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<a href="http://abicheck.sourceforge.net/">http://abicheck.sourceforge.net/</a>
|
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</p>
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<p>
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C++ ABI reference
|
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http://www.codesourcery.com/cxx-abi/
|
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<br />
|
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<a href="http://www.codesourcery.com/cxx-abi/">http://www.codesourcery.com/cxx-abi/</a>
|
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</p>
|
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|
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<p>
|
||||
Intel ABI documentation
|
||||
<br />
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"Intel® Compilers for Linux* -Compatibility with the GNU Compilers"
|
||||
<br />
|
||||
(included in icc 6.0)
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</p>
|
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|
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<p>
|
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Sun Solaris 2.9 docs
|
||||
<br />
|
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Linker and Libraries Guide (document 816-1386)
|
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<br />
|
||||
C++ Migration Guide (document 816-2459)
|
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http://docs.sun.com/db/prod/solaris.9
|
||||
http://docs.sun.com/?p=/doc/816-1386&a=load
|
||||
<br />
|
||||
<a href="http://docs.sun.com/db/prod/solaris.9">http://docs.sun.com/db/prod/solaris.9</a>
|
||||
<br />
|
||||
<a href="http://docs.sun.com/?p=/doc/816-1386&a=load">http://docs.sun.com/?p=/doc/816-1386&a=load</a>
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Ulrich Drepper, "ELF Symbol Versioning"
|
||||
http://people.redhat.com/drepper/symbol-versioning
|
||||
<br />
|
||||
<a href="http://people.redhat.com/drepper/symbol-versioning">http://people.redhat.com/drepper/symbol-versioning</a>
|
||||
</p>
|
||||
|
||||
</body>
|
||||
</html>
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user