diff options
author | Boris Kolpackov <boris@codesynthesis.com> | 2021-10-14 09:06:50 +0200 |
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committer | Boris Kolpackov <boris@codesynthesis.com> | 2021-10-14 09:06:50 +0200 |
commit | 4ae6c2fe91d8dc5bdb7f6d9808b097dde8a8265f (patch) | |
tree | 06ae11143ba24415188afc1e0352d29e5278ef1d /doc/manual.cli | |
parent | c08bf939d0d9ee475f5553135ad4dbe3e5684f3b (diff) |
Move symbol exporting documentation from NEWS to manual
Diffstat (limited to 'doc/manual.cli')
-rw-r--r-- | doc/manual.cli | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/doc/manual.cli b/doc/manual.cli index d63e887..e941b6b 100644 --- a/doc/manual.cli +++ b/doc/manual.cli @@ -6640,6 +6640,52 @@ otherwise share the same header search paths, for example, as a family of libraries), then the whitelist may not be effective. +\h#cc-auto-symexport|Automatic DLL Symbol Exporting| + +The \c{bin.def} module (automatically loaded by the \c{c} and \c{cxx} modules +for the \c{*-win32-msvc} targets) provides a rule for generating +symbol-exporting \c{.def} files. This allows automatically exporting all +symbols for all the Windows targets/compilers using the following arrangement +(showing for \c{cxx} in this example): + +\ +lib{foo}: libul{foo}: {hxx cxx}{**} ... + +lib{foo}: def{foo}: include = ($cxx.target.system == 'win32-msvc') +def{foo}: libul{foo} + +if ($cxx.target.system == 'mingw32') + cxx.loptions += -Wl,--export-all-symbols +\ + +That is, we use the \c{.def} file approach for MSVC (including when building +with Clang) and the built-in support (\c{--export-all-symbols}) for MinGW. + +Note that it is also possible to use the \c{.def} file approach for MinGW. In +this case we need to explicitly load the \c{bin.def} module (which should be +done after loading \c{c} or \c{cxx}) and can use the following arrangement: + +\ +# root.build + +using cxx +using bin.def +\ + +\ +lib{foo}: libul{foo}: {hxx cxx}{**} ... + +lib{foo}: def{foo}: include = ($cxx.target.class == 'windows') +def{foo}: libul{foo} +\ + +Note also that this only deals with exporting of the symbols from a DLL. In +order to work, code that uses such a DLL should be able to import the symbols +without explicit \c{__declspec(dllimport)} declarations. This works thanks +to the symbol auto-importing support in Windows linkers. Note, however, that +auto-importing only works for functions and not for global variables. + + \h#cc-gcc|GCC Compiler Toolchain| The GCC compiler id is \c{gcc}. |