[Devel] shared library under Windows

[Tor Lillqvist]

Thierry Frey writes:
 > Is there an easy way to build FT2 as a shared library under Windows ?

Not easy, but not hard either. I *had* to build freetype as a DLL,
otherwise the application didn't work for me. I can't remember the
details exactly, probably the problem was that if you have an .exe
linked to a static library, and a DLL also linked to the same static
library, these two library instances have separate copies of their
global variables. This causes strange problems, if the .exe code
passes data related to its copy of the library to the DLL which passes
it to its copy... With a DLL, there is only one copy of the library
and its global variables. How does Unix behave in cases like this?)

You have to modify the .mk files somewhat. I used the following
quickly hacked link_dll.mk file:

#
#  Link instructions for building a DLL on Win32
#


# Copyright 1996-2000 by
# David Turner, Robert Wilhelm, and Werner Lemberg.
#
# This file is part of the FreeType project, and may only be used, modified,
# and distributed under the terms of the FreeType project license,
# LICENSE.TXT.  By continuing to use, modify, or distribute this file you
# indicate that you have read the license and understand and accept it
# fully.


ifdef BUILD_PROJECT

  .PHONY: clean_project distclean_project

  # Now include the main sub-makefile.  It contains all the rules used to
  # build the library with the previous variables defined.
  #
  include $(TOP)/builds/$(PROJECT).mk

  PROJECT_VERSION := 2.0

  PROJECT_LIBRARY_BASENAME := $(LIBRARY)-$(PROJECT_VERSION).dll
  PROJECT_LIBRARY := $(LIB_)$(PROJECT_LIBRARY_BASENAME)
  PROJECT_GCC_IMPORT_LIBRARY := lib$(LIBRARY)-$(PROJECT_VERSION).a
  PROJECT_MSVC_IMPORT_LIBRARY := $(LIBRARY)-$(PROJECT_VERSION).lib

  # The cleanup targets.
  #
  clean_project: clean_project_dos
  distclean_project: distclean_project_dos

  # This final rule is used to link all object files into a single library.
  # this is compiler-specific
  #
  $(PROJECT_LIBRARY): $(OBJECTS_LIST)
    ifdef CLEAN_LIBRARY
          -$(CLEAN_LIBRARY) $(NO_OUTPUT)
    endif
        /src/glib/build-dll $(LIBRARY) $(PROJECT_VERSION) 
$(TOP)/builds/$(LIBRARY).def $(OBJECTS_LIST)
        mv $(PROJECT_LIBRARY_BASENAME) $(LIB_)
        mv $(PROJECT_GCC_IMPORT_LIBRARY) $(LIB_)
        mv $(PROJECT_MSVC_IMPORT_LIBRARY) $(LIB_)

endif

# EOF

Here is the freetype.def file I used:

EXPORTS
        FTC_Image_Cache_Lookup
        FTC_Image_Cache_New
        FTC_Manager_Done
        FTC_Manager_Lookup_Face
        FTC_Manager_Lookup_Size
        FTC_Manager_New
        FTC_Manager_Reset
        FT_Access_Frame
        FT_Add64
        FT_Add_Default_Modules
        FT_Add_Module
        FT_Alloc
        FT_Attach_File
        FT_Attach_Stream
        FT_Create_Extensions
        FT_Destroy_Extensions
        FT_Div64by32
        FT_DivFix
        FT_Done_Extensions
        FT_Done_Face
        FT_Done_FreeType
        FT_Done_Glyph
        FT_Done_GlyphSlot
        FT_Done_Library
        FT_Done_Memory
        FT_Done_Size
        FT_Done_Stream
        FT_Extract_Frame
        FT_Forget_Frame
        FT_Free
        FT_Get_Char
        FT_Get_Char_Index
        FT_Get_Extension
        FT_Get_Glyph
        FT_Get_Glyph_Name
        FT_Get_Kerning
        FT_Get_Long
        FT_Get_LongLE
        FT_Get_Module
        FT_Get_Module_Interface
        FT_Get_Multi_Master
        FT_Get_Offset
        FT_Get_Renderer
        FT_Get_Sfnt_Table
        FT_Get_Short
        FT_Get_ShortLE
        FT_GlyphLoader_Add
        FT_GlyphLoader_Check_Points
        FT_GlyphLoader_Check_Subglyphs
        FT_GlyphLoader_Copy_Points
        FT_GlyphLoader_Create_Extra
        FT_GlyphLoader_Done
        FT_GlyphLoader_New
        FT_GlyphLoader_Prepare
        FT_GlyphLoader_Reset
        FT_GlyphLoader_Rewind
        FT_Glyph_Copy
        FT_Glyph_Get_CBox
        FT_Glyph_To_Bitmap
        FT_Glyph_Transform
        FT_Init_Extensions
        FT_Init_FreeType
        FT_List_Add
        FT_List_Finalize
        FT_List_Find
        FT_List_Insert
        FT_List_Iterate
        FT_List_Remove
        FT_List_Up
        FT_Load_Char
        FT_Load_Glyph
        FT_Lookup_Renderer
        FT_Lru_Done
        FT_Lru_Lookup
        FT_Lru_Lookup_Node
        FT_Lru_New
        FT_Lru_Remove_Node
        FT_Lru_Remove_Selection
        FT_Lru_Reset
        FT_Matrix_Invert
        FT_Matrix_Multiply
        FT_MulDiv
        FT_MulFix
        FT_MulTo64
        FT_New_Face
        FT_New_GlyphSlot
        FT_New_Library
        FT_New_Memory
        FT_New_Memory_Face
        FT_New_Memory_Stream
        FT_New_Size
        FT_New_Stream
        FT_Open_Face
        FT_Outline_Copy
        FT_Outline_Decompose
        FT_Outline_Done
        FT_Outline_Done_Internal
        FT_Outline_Get_Bitmap
        FT_Outline_Get_CBox
        FT_Outline_New
        FT_Outline_New_Internal
        FT_Outline_Render
        FT_Outline_Reverse
        FT_Outline_Transform
        FT_Outline_Translate
        FT_Read_Char
        FT_Read_Fields
        FT_Read_Long
        FT_Read_LongLE
        FT_Read_Offset
        FT_Read_Short
        FT_Read_ShortLE
        FT_Read_Stream
        FT_Read_Stream_At
        FT_Realloc
        FT_Register_Extension
        FT_Release_Frame
        FT_Remove_Module
        FT_Render_Glyph
        FT_Render_Glyph_Internal
        FT_Seek_Stream
        FT_Select_Charmap
        FT_Set_Char_Size
        FT_Set_Charmap
        FT_Set_Debug_Hook
        FT_Set_MM_Blend_Coordinates
        FT_Set_MM_Design_Coordinates
        FT_Set_Pixel_Sizes
        FT_Set_Renderer
        FT_Set_Transform
        FT_Skip_Stream
        FT_Sqrt64
        FT_Stream_Pos
        FT_Vector_Transform
        TT_New_Context
        TT_RunIns

Hope this helps,
--tml