Windows: Optionally generate DLL module definition files automatically

Create target property WINDOWS_EXPORT_ALL_SYMBOLS to automatically
generate a module definition file from MS-compatible .obj files and give
it to the linker in order to export all symbols from the .dll part of a
SHARED library.

1 files changed, 18 insertions, 0 deletions

diff --git a/Help/prop_tgt/WINDOWS_EXPORT_ALL_SYMBOLS.rst b/Help/prop_tgt/WINDOWS_EXPORT_ALL_SYMBOLS.rst
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+WINDOWS_EXPORT_ALL_SYMBOLS
+--------------------------
+
+This property is implemented only for MS-compatible tools on Windows.
+
+Enable this boolean property to automatically create a module definition
+(``.def``) file with all global symbols found in the input ``.obj`` files
+for a ``SHARED`` library on Windows.  The module definition file will be
+passed to the linker causing all symbols to be exported from the ``.dll``.
+For global *data* symbols, ``__declspec(dllimport)`` must still be used when
+compiling against the code in the ``.dll``.  All other function symbols will
+be automatically exported and imported by callers.  This simplifies porting
+projects to Windows by reducing the need for explicit ``dllexport`` markup,
+even in ``C++`` classes.
+
+This property is initialized by the value of
+the :variable:`CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS` variable if it is set
+when a target is created.