Borland C++ Builder LoadFromResourceID Results in EAccess Violation - c++

Question

I'm using Borland C++Builder 5 to write a game program. I'm trying to load a bitmap from a resource file I created. I cannot get the bitmap to load from
the resource file either by ID or by Name. It will load from file, but I want
to use the resource file. Loading from ID or Name results in the following error message at runtime:
Project HoldemProbs.exe raised exception class EAcessViolation with message
'Access violation at address 0043F66E in module 'HoldemProbs.exe'.
Read of address 000003EB. Process stopped. Use Step or Run to continue.
I'm pretty new to C++ and C++Builder, and I am sure I am doing something wrong. I just can't figure out what. I think it probably has something to do with the HInstance value, but I don't know what.
Below are relevant pieces of code:
ResRC.h
#ifndef RESRC_H
#define RESRC_H
#define RC_REDBACK 1000
#endif
RedBack.rc
RC_REDBACK BITMAP "<MYSOURCEPATH>\RedBack.bmp"
HoldemProbs.cpp
#include <vcl.h>
#pragma hdrstop
USERES("HoldemProbs.res");
USEFORM("..\Source\HoldemCalc.cpp", Form1);
USERES("..\Source\RedBack.res");
WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int)
{
try
{
Application->Initialize();
Application->Title = "HoldemEval";
Application->CreateForm(__classid(TForm1), &Form1);
Application->Run();
}
catch (Exception &exception)
{
Application->ShowException(&exception);
}
return 0;
}
HoldemCalc.cpp
#include <vcl.h>
#include <cstring.h>
#include <HoldemEval.hpp>
#include <Graphics.hpp>
#pragma hdrstop
#pragma resource "*.dfm"
#include <Graphics.hpp>
#include <ResRC.h>
#include "HoldemCalc.h"
#include <string>
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
CardBackTst(); //Run test of card back bitmap useage
}
CardBackTst.cpp
void CardBackTst(void){
Graphics::TBitmap* RedBack = new Graphics::TBitmap;
Form1 -> Debug -> Text = DEBUGTEXT; //See below for DEBUGTEXT
RedBack -> LoadFromResourceID ((ARG1),RC_REDBACK); //See below for ARG1
}
There is an Edit Box called Debug used to display debug information. At various times, DEBUGTEXT has been (w/o surrounding "s):
"(int)(GetModuleHandle(NULL)"
"reinterpret_cast<int>(HInstance)"
"(int)HInstance"
"(int)(GetModuleHandle("<MYFINALPATH>\\HoldemProbs.exe"))" // ANSI string
"RC_REDBACK" (This yielded the correct value -- 1000)
"reinterpret_cast<int>(RedBack -> Handle)"
"(int)(Form1 -> Handle)"
At various times, ARG1 has been each of the above values of DEBUGTEXT, except for RC_REDBACK. All have resulted in an EAccessViolation error.
The following statement to load from the resource name has been used
with each ARG1 value, with the same EAcessViolation result:
RedBack -> LoadFromResourceName ((ARG1),"MYPATH\\RedBack.bmp");
However, the following LoadFromFile() statement to load from the actual bitmap file does work:
RedBack -> LoadFromFile("MYPATH\\RedBack.bmp");

Answer 1

I see two problems with this code:
RedBack.rc does not have a #include "ResRC.h" statement:
#include "ResRC.h" // <-- add this!
RC_REDBACK BITMAP "<MYSOURCEPATH>\RedBack.bmp"
Without that, RC_REDBACK will not be #defined, and so the bitmap resource will be identified by the literal name "RC_REDBACK" and not by the ID number 1000. As such, you will have to use LoadFromResouceName() instead of LoadFromResourceID():
RedBack->LoadFromResourceName((unsigned)HInstance, "RC_REDBACK");
Use a resource viewer tool to verify how your resources are actually identified in the final executable.
inside of CardBackTst(), the global Form1 pointer may not have been assigned yet, since the TForm1 object is still being constructed. CardBackTst() should not be relying on the global pointer at all. It should take the Form pointer as an input parameter instead:
//#include "ResRC.h"
void CardBackTst(TForm1 *Form) {
Graphics::TBitmap* RedBack = new Graphics::TBitmap;
if (Form) Form->Debug->Text = DEBUGTEXT;
//RedBack->LoadFromResourceID((unsigned)HInstance, RC_REDBACK);
RedBack->LoadFromResourceName((unsigned)HInstance, "RC_REDBACK");
}
...
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
CardBackTst(this);
}
A better solution would be to pass in the TEdit directly instead of the TForm itself:
//#include "ResRC.h"
void CardBackTst(TEdit *Debug) {
Graphics::TBitmap* RedBack = new Graphics::TBitmap;
if (Debug) Debug->Text = DEBUGTEXT;
//RedBack->LoadFromResourceID((unsigned)HInstance, RC_REDBACK);
RedBack->LoadFromResourceName((unsigned)HInstance, "RC_REDBACK");
}
...
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
CardBackTst(Debug);
}
Or, use a callback function instead:
//#include "ResRC.h"
typedef void __fastcall (__closure *TCardDebugProc)(const String &);
void CardBackTst(TCardDebugProc DebugProc) {
Graphics::TBitmap* RedBack = new Graphics::TBitmap;
if (DebugProc) DebugProc(DEBUGTEXT);
//RedBack->LoadFromResourceID((unsigned)HInstance, RC_REDBACK);
RedBack->LoadFromResourceName((unsigned)HInstance, "RC_REDBACK");
}
...
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
CardBackTst(&LogDebug);
}
void __fastcall TForm1::LogDebug(const String &DebugText)
{
Debug->Text = DebugText;
}