/Gh (Enable _penter Hook Function)
Causes a call to the _penter function at the start of every method or function.
/Gh
Remarks
The _penter function is not part of any library and it is up to you to provide a definition for _penter.
Unless you plan to explicitly call _penter, you do not need to provide a prototype. The function must appear as if it had the following prototype, and it must push the content of all registers on entry and pop the unchanged content on exit:
void __declspec(naked) _cdecl _penter( void );
To set this compiler option in the Visual Studio development environment
Open the project's Property Pages dialog box. For details, see How to: Open Project Property Pages.
Click the C/C++ folder.
Click the Command Line property page.
Type the compiler option in the Additional Options box.
To set this compiler option programmatically
- See AdditionalOptions.
Example
The following code, when compiled with /Gh, shows how _penter is called twice; once when entering function main and once when entering function x.
// Gh_compiler_option.cpp
// compile with: /Gh
// processor: x86
#include <stdio.h>
void x() {}
int main() {
x();
}
extern "C" void __declspec(naked) _cdecl _penter( void ) {
_asm {
push eax
push ebx
push ecx
push edx
push ebp
push edi
push esi
}
printf_s("\nIn a function!");
_asm {
pop esi
pop edi
pop ebp
pop edx
pop ecx
pop ebx
pop eax
ret
}
}
Sample Output
In a function! In a function!