typedef XS(foo) - fails in C++ /w 5.10.0

Outlined below is a problem I ran into today followed by a suggested
fix.

 

First, some background information. XSUB.h in 5.8.8. defined the macro
XS(name) as such:

 

===== START CODE =====

 

    #if defined(__CYGWIN__) && defined(USE_DYNAMIC_LOADING)

    #  define XS(name) __declspec(dllexport) void name(pTHX_ CV* cv)

    #else

    #  ifdef HASATTRIBUTE_UNUSED

    #    define XS(name) void name(pTHX_ CV* cv __attribute__unused__)

    #  else

    #    define XS(name) void name(pTHX_ CV* cv)

    #  endif

    #endif

 

===== END CODE =====

 

 

The main version of the definition I'm interested is "#define XS(name)
void name(pTHX_ CV* cv)".

 

In 5.10.0 these definitions changed to the following:

 

===== START CODE =====

 

    /* XSPROTO() is also used by SWIG like this:

     *

     *     typedef XSPROTO(SwigPerlWrapper);

     *     typedef SwigPerlWrapper *SwigPerlWrapperPtr;

     *

     * This code needs to be compilable under both C and C++.

     *

     * Don't forget to change the __attribute__unused__ version of XS()

     * below too if you change XSPROTO() here.

     */

    #define XSPROTO(name) void name(pTHX_ CV* cv)

    

    #undef XS

    #if defined(__CYGWIN__) && defined(USE_DYNAMIC_LOADING)

    #  define XS(name) __declspec(dllexport) XSPROTO(name)

    #endif

    #if defined(__SYMBIAN32__)

    #  define XS(name) EXPORT_C XSPROTO(name)

    #endif

    #ifndef XS

    #  if defined(HASATTRIBUTE_UNUSED) && !defined(__cplusplus)

    #    define XS(name) void name(pTHX_ CV* cv __attribute__unused__)

    #  else

    #    ifdef __cplusplus

    #      define XS(name) extern "C" XSPROTO(name)

    #    else

    #      define XS(name) XSPROTO(name)

    #    endif

    #  endif

    #endif

 

===== END CODE =====

 

 

The main definition I'm interested here is the __cplusplus specific one:
"#define XS(name) extern "C" XSPROTO(name)".

 

== THE PROBLEM ==

 

I have some code (namely XML::Xerces-2.7.0-0's Xerces.cpp source file)
which does one of these:

 

    *code*: typedef XS(SwigPerlWrapper);

 

Now, on 5.8.8 this would evaluate to something the following statement,
which is all well and good:

 

    *code*: typedef void SwigPerlWrapper(pTHX_ CV* cv);

 

However, on 5.10.0 it evaluates to:

 

    *code*: typedef extern "C" void SwigPerlWrapper(pTHX_ CV* cv);

 

The "extern "C"" part makes the compiler die with the following message:

 

error: expected unqualified-id before string constant

error: expected `,' or `;' before string constant

 

 

== PROPOSED FIX ==

 

I propose that there be a new macro added called XS_TYPEDEF. This macro
would be defined in the usual way when __cplusplus is not present:

 

#define XS_TYPEDEF(name) typedef XS(name)

 

However, when __cplusplus is defined it would be set to something like
this:

 

#define XS_TYPEDEF(name) extern "C" { typedef XS(name); }

 

What do you guys think?

 

-Patrick

 

• typedef XS(foo) - fails in C++ /w 5.10.0 by Patrick Rutkowski
• typedef XS(foo) - fails in C++ /w 5.10.0 by Patrick Rutkowski
• typedef XS(foo) - fails in C++ /w 5.10.0 by Patrick Rutkowski
• RE: typedef XS(foo) - fails in C++ /w 5.10.0 by Jan Dubois
• RE: typedef XS(foo) - fails in C++ /w 5.10.0 by Patrick Rutkowski