GenerateExportHeader: Add option to specify custom content

Help/release/dev/GenerateExportHeader-custom-content.rst

@@ -0,0 +1,6 @@
+GenerateExportHeader-custom-content
+-----------------------------------
+
+* The :module:`GenerateExportHeader` module learned a new
+  ``CUSTOM_CONTENT_FROM_VARIABLE`` option to specify a variable
+  containing custom content for inclusion in the generated header.

Modules/GenerateExportHeader.cmake

@@ -20,6 +20,7 @@
 #              [NO_DEPRECATED_MACRO_NAME <no_deprecated_macro_name>]
 #              [DEFINE_NO_DEPRECATED]
 #              [PREFIX_NAME <prefix_name>]
+#              [CUSTOM_CONTENT_FROM_VARIABLE <variable>]
 #    )
 #
 #
@@ -60,8 +61,10 @@
 # The CMake fragment will generate a file in the
 # ``${CMAKE_CURRENT_BINARY_DIR}`` called ``somelib_export.h`` containing the
 # macros ``SOMELIB_EXPORT``, ``SOMELIB_NO_EXPORT``, ``SOMELIB_DEPRECATED``,
-# ``SOMELIB_DEPRECATED_EXPORT`` and ``SOMELIB_DEPRECATED_NO_EXPORT``.  The
-# resulting file should be installed with other headers in the library.
+# ``SOMELIB_DEPRECATED_EXPORT`` and ``SOMELIB_DEPRECATED_NO_EXPORT``.
+# They will be followed by content taken from the variable specified by
+# the ``CUSTOM_CONTENT_FROM_VARIABLE`` option, if any.
+# The resulting file should be installed with other headers in the library.
 #
 # The ``BASE_NAME`` argument can be used to override the file name and the
 # names used for the macros:
@@ -288,7 +291,7 @@ macro(_DO_GENERATE_EXPORT_HEADER TARGET_LIBRARY)
   set(options DEFINE_NO_DEPRECATED)
   set(oneValueArgs PREFIX_NAME BASE_NAME EXPORT_MACRO_NAME EXPORT_FILE_NAME
     DEPRECATED_MACRO_NAME NO_EXPORT_MACRO_NAME STATIC_DEFINE
-    NO_DEPRECATED_MACRO_NAME)
+    NO_DEPRECATED_MACRO_NAME CUSTOM_CONTENT_FROM_VARIABLE)
   set(multiValueArgs)
 
   cmake_parse_arguments(_GEH "${options}" "${oneValueArgs}" "${multiValueArgs}"
@@ -361,6 +364,14 @@ macro(_DO_GENERATE_EXPORT_HEADER TARGET_LIBRARY)
   endif()
   string(MAKE_C_IDENTIFIER ${EXPORT_IMPORT_CONDITION} EXPORT_IMPORT_CONDITION)
 
+  if(_GEH_CUSTOM_CONTENT_FROM_VARIABLE)
+    if(DEFINED "${_GEH_CUSTOM_CONTENT_FROM_VARIABLE}")
+      set(CUSTOM_CONTENT "${${_GEH_CUSTOM_CONTENT_FROM_VARIABLE}}")
+    else()
+      set(CUSTOM_CONTENT "")
+    endif()
+  endif()
+
   configure_file("${_GENERATE_EXPORT_HEADER_MODULE_DIR}/exportheader.cmake.in"
     "${EXPORT_FILE_NAME}" @ONLY)
 endmacro()

Modules/exportheader.cmake.in

@@ -38,5 +38,5 @@
 #    define @NO_DEPRECATED_MACRO_NAME@
 #  endif
 #endif
-
+@CUSTOM_CONTENT@
 #endif

Tests/Module/GenerateExportHeader/lib_shared_and_static/CMakeLists.txt

@@ -25,9 +25,12 @@ add_library(shared_variant SHARED ${lib_SRCS})
 set_target_properties(shared_variant PROPERTIES DEFINE_SYMBOL SHARED_VARIANT_MAKEDLL)
 add_library(static_variant ${lib_SRCS})
 
+set(MY_CUSTOM_CONTENT "#define MY_CUSTOM_CONTENT_ADDED")
+
 generate_export_header(shared_variant
   BASE_NAME libshared_and_static
   PREFIX_NAME MYPREFIX_
+  CUSTOM_CONTENT_FROM_VARIABLE MY_CUSTOM_CONTENT
 )
 
 set_target_properties(static_variant PROPERTIES COMPILE_FLAGS -DLIBSHARED_AND_STATIC_STATIC_DEFINE)

Tests/Module/GenerateExportHeader/lib_shared_and_static/libshared_and_static.cpp

@@ -1,6 +1,10 @@
 
 #include "libshared_and_static.h"
 
+#ifndef MY_CUSTOM_CONTENT_ADDED
+# error "MY_CUSTOM_CONTENT_ADDED not defined!"
+#endif
+
 int LibsharedAndStatic::libshared_and_static() const
 {
   return 0;