[ft-devel] how to forbid to link public-but-unrecommended function in libfreetype.dylib?

[mpsuzuki]

Dear Sirs,

As I've written in previous post, for MacOSX, I want to replace
Carbon-based MacOS font support by Carbon-free implementation.
However, a few functions using MacOS specific legacy datatypes
(like FSSpec which cannot handle long UTF-8 filename) in their
arguments cannot be replaced. When freetype2 is built on modern
MacOSX systems, using such functions is not recommended.
On the other hand, the legacy systems like classic MacOS/m68k
don't know modern datatypes, the functions using legacy datatypes
are essential. (the binary executable format for classic MacOS:
CEF cannot be mixed with Mach-O, thus, different framework for
classic MacOS and MacOSX won't cause serious problem)

Due to this discontinuity, moving all of unrecommended functions
to internal headers (regardless of the system) is not good idea.

Some Unix desktop applications on MacOSX using freetype2 are
growing up bigger and bigger, and runtime testing before release
is insufficient. Thus, runtime warning message is insufficient
to notice "unrecommended function is used" to the developer.

So, I wish if I could forbid (or disturb) the functions in building
phase of the problematic application. Of course, keeping the function
available for runtime linker is important (to avoid users from
"unresolved symbol" trouble). There's any standard method to issue
an error in cc1, with meaningful informative message?

I tried a trick in attached patch. Possibly, even if the application
uses unrecommended function, it will include header file which defines
the function's interface. Thus, if I replace the unrecommended
functions by uncompilable macro functions when building procedure
is not for libfreetype, the building procedure of the application
will be interrupted.

Also I insert undeclared variable array, so cc1 will issue an
error including the variable name, so the variable name can be
used to show some message to developer.

However, this trick is very very ugly. There's any better method?


Regards,
mpsuzuki


--- freetype2/include/freetype/ftmac.h
+++ freetype2/include/freetype/ftmac.h
@@ -92,6 +92,11 @@
                          FT_Face    *aface );
 
 
+#if !defined(FT2_BUILD_LIBRARY)
+#define        FT_GetFile_From_Mac_Name(a, b, c)       { 
FT_GetFile_From_Mac_Name_uses_obsolete_FSSpec[]; }
+#define        FT_GetFile_From_Mac_ATS_Name(a, b, c)   { 
FT_GetFile_From_Mac_ATS_Name_uses_obsolete_FSSpec[]; }
+#define        FT_New_Face_From_FSSpec(a, b, c)        { 
FT_New_Face_From_FSSpec_uses_obsolete_FSSpec[]; }
+#else
   /*************************************************************************/
   /*                                                                       */
   /* <Function>                                                            */
@@ -175,6 +180,7 @@
                            const FSSpec  *spec,
                            FT_Long        face_index,
                            FT_Face       *aface );
+#endif
 
 
   /*************************************************************************/