Compiling as C

[AJenbo]

This issue is for tracking the status of converting the project to C in order to get things more binary exact.

General issue

• storm.h isn't loaded in a way that allows the compiler to recognize the function names.
• diabloui.h isn't loaded in a way that allows the compiler to recognize the function names.
• static float *_cpp_init_value = INFINITY; this was probably put here by the compiler because of crtical sections or similar and should be safe to remove for now.
• ddraw.h isn't being referenced in a way that allows the compiler to recognize the structure memberse.
• dsound.h isn't being referenced in a way that allows the compiler to recognize the structure memberse.
• We need a C replacment for init_event, this is relatet to the _cpp_init_ structures. C init #549
  • dthread.cpp
  • dx.cpp init
  • logging.cpp
  • fault.cpp
  • msgcmd.cpp
  • nthread.cpp
• Some functions still use C++ only helpers (__ROR2__, __ROR4__, __OFSUB__)
  • control.cpp
    • DrawSpellCel Replace __ROR4__ stdlib, make _ROR2__ C frindly #540
    • CheckChrBtns
    • control_set_gold_curs
  • drlg_l3.cpp
    • DRLG_L3River Clean up __OFSUB__ usage #539
  • engine.cpp
    • CelDecDatLightTrans Replace __ROR4__ stdlib, make _ROR2__ C frindly #540
    • Cel2DecDatLightTrans Replace __ROR4__ stdlib, make _ROR2__ C frindly #540
  • items.cpp
    • GetItemSpace
  • lighting.cpp
    • DoLighting Clean up __OFSUB__ usage #539
  • monster.cpp
    • M_TryH2HHit Clean up __OFSUB__ usage #539
    • MAI_Counselor Clean up __OFSUB__ usage #539
  • objects.cpp
    • AddSarc
    • AddBarrel
    • Obj_FlameTrap
    • Obj_Trap
    • MonstCheckDoors
    • OperateL1Door
    • OperateL2Door
  • stores.cpp
    • StoreSellItem Clean up __OFSUB__ usage #539
    • S_SRepairEnter Clean up __OFSUB__ usage #539
    • S_WRechargeEnter Clean up __OFSUB__ usage #539
    • HealerBuyItem Clean up __OFSUB__ usage #539
    • CheckStoreBtn Clean up __OFSUB__ usage #539

File issues

• appfat.cpp Byte-identical version of appfat_cpp_init. #110
  • delete is being overloaded
• capture.cpp
  • Looks like we are missing io.h
• diablo.cpp
  • looks like we need winuser.h
  • line 297 char szValueName[] = "Intro";
• missiles.cpp
  • unsigned char Dirs[16][16] = {...} needs to be rewritten in a C friendly way.
• movie.cpp (Compile movie.cpp as C #529)
  • LRESULT return type appears to not allow NULL, use 0?
• mpqapi.cpp Compile mpqapi.cpp as C #554
  • mpqapi_open_archive(const char *pszArchive, ...) first parameter gives the following errors C4028, C4090, C4024
• pfile.cpp
  • char password[16] = PASSWORD_SINGLE; needs to be rewritten in a C friendly way.
• wave.cpp
  • SFileReadFile(1,2,3,4,NULL) produce an error
• render.cpp
  • asm_* the C compiler is unhappy with the inline format. Make inline statments C compatible #550
  • asm_* dst & src are passed by references, this isn't allowed in C.

[squidcc]

char password[16] = PASSWORD_SINGLE; needs to be rewritten in a C friendly way.

There is nothing wrong with that line, it's perfectly valid C.
Same goes for the SFileReadFile() comments, the code is already correct. The header is not; lpDistanceToMoveHigh should be a LONG pointer, that's why it begins with lp.

No idea what supposed issue there is with dsound.h and ddraw.h, those are standard windows headers and work fine with both C and C++ code.

[AJenbo]

In C89 variables must be declare at the beginning of a scope block. If you look in pfile.cpp you will see that the line appear in several places where it brakes this rule.

Try compiling dx.cpp as C and you will see the error messages.

[squidcc]

The referenced line in pfile.cpp is always at the beginning of a scope block (before any non-declaration statements).

[AJenbo]

@squidcc are there any of the issues you would be interested in tackling?

The referenced line in pfile.cpp is always at the beginning of a scope block (before any non-declaration statements).

Doesn't look like it to me, and the compiler defiantly complains.

[squidcc]

Doesn't look like it to me, and the compiler defiantly complains.

That's because you recently broke it: b5f69dc#diff-c4e4c37d0d99140aa6835fdfc1d1ae87L322

It was perfectly valid C before you hoisted those other declarations out for no apparent reason.

[mewmew]

It was perfectly valid C before you hoisted those other declarations out for no apparent reason.

@squidcc To provide some background. The translation process from C++ to C is a rather large undertaking. To make it easier, both to write, and to review, we've decided to split the processes into smaller subtasks. One of those tasks is to move declarations to the top. The specific change related to the password variable is just one out of many in a much larger undertaking, and as such, the main intention with these subtasks is to make the scope of each task narrow, to facilitate review.

It is an iterative process, and by the choice of scope each iteration will not be in a "perfect" state, but rather move the entire project closer in the direction of being compilable as C. Once we reach this goal, we can once more re-focus our efforts on bin perfect and take one function at the time.

Any recommendations on how to do this translation from C++ to C in as easy a way as possible is much appreciated.

Kindly,
Robni

[squidcc]

The only way you're going to get that function (functions? I don't remember) bin-exact is having that password string initialized at that point in the function, not the beginning. It was already valid C code so all you're doing is breaking it now so it can be put back exactly the same way later.

Again, there was no need to modify that code, it was already C89 compatible. There was nothing to write, nothing to review, nothing to iterate. It didn't need to be touched, and now it's broken.

Any recommendations on how to do this translation from C++ to C in as easy a way as possible is much appreciated.

You could simply revert it instead of trying to justify a mistake.

[mewmew]

The list of files that do not yet compile as C, as of rev ca64011.

• delete operator

  • Source/appfat.cpp

• cinit

  • Source/dthread.cpp
  • Source/dx.cpp
  • Source/engine.cpp
  • Source/fault.cpp
  • Source/logging.cpp
  • Source/msgcmd.cpp
  • Source/nthread.cpp