# New Ticket Created by "Adam Thomason" # Please include the string: [perl #24247] # in the subject line of all future correspondence about this issue. # <URL: http://rt.perl.org/rt2/Ticket/Display.html?id=24247 >
The extension code has some type safety troubles. For instance, when PARROT_IN_CORE is defined, Parrot_CharType is declared by #define Parrot_CharType struct parrot_chartype_t * in include/parrot/chartype.h. However, outside of the core, include/parrot/extend.h instead declares it as typedef void * Parrot_CharType; This causes problems because Parrot_find_chartype returns a "const Parrot_CharType". In the core, this is ok, because it expands via the preprocessor to "const struct parrot_chartype_t *", which is a valid return type. However, when compiling an extension, the typedef causes "const Parrot_CharType" to become a "struct parrot_chartype_t * const", which is not the same and is seemingly an illegal return type according to VisualAge C (*1). On account of this, it refuses to compile code in extend.t which includes extend.h. The same problem applies to Parrot_Encoding vis-a-vis Parrot_find_encoding. There are two solutions, both of which involve making the declarations consistent. Either use #define's in extend.h as in chartype.h for Parrot_CharType and encoding.h for Parrot_Encoding, or create an extra typedef for each (e.g. Parrot_Const_CharType). I tend to avoid the preprocessor for type magic when possible, so I've opted to make the latter changes (*2), even though it requires extra definitions. If there's a reason they were originally #define'd, that should work also, but I haven't tried it. *1) Googling around seems to indicate that ANSI C doesn't allow return types to be const- or volatile-qualfied. "const struct parrot_chartype_t *" is a non-const pointer to const, which is okay; "struct parrot_chartype_t * const" is a const pointer to non-const, which is thus illegal. I don't see anything in the C99 final draft concerning this, so the restriction might have been lifted to match C++ semantics (passing -qlanglvl=C99 to xlc turns the error into a warning, which partly supports that theory). Which version are we targetting anyway? I don't see a definitive statement anywhere in docs/. *2) Patch attached, extend tests now pass on AIX and don't break Gentoo. -- Adam Thomason [EMAIL PROTECTED]
