Compiler Warning (level 1) C4378
Visual Studio 2015
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The latest version of this topic can be found at Compiler Warning (level 1) C4378.
Must obtain function pointers to run initializers; consider System::ModuleHandle::ResolveMethodHandle
Under /clr, initializer symbols contain function tokens, not functions pointers. You need to convert tokens to pointers using ResolveMethodHandle.
The following sample generates C4378.
// C4378.cpp
// compile with: /W1 /clr /c
typedef void (__cdecl *PF)(void);
int cxpf = 0; // number of destructors to call
PF pfx[200]; // ptrs to those dtors, watch for overflow
int myexit (PF pf) {
pfx[cxpf++] = pf;
return 0;
}
struct A {
A() {}
~A() {}
};
A aaaa;
#pragma data_seg(".mine$a")
PF InitSegStart = (PF)1;
#pragma data_seg(".mine$z")
PF InitSegEnd = (PF)1;
#pragma data_seg()
void InitializeObjects () {
PF *x = &InitSegStart;
for (++x ; x < &InitSegEnd ; ++x)
if (*x)
(*x)();
}
#pragma init_seg(".mine$m",myexit) // C4378
A bbbb; // crash
int main () {
InitializeObjects();
}
The following sample shows how to resolve C4378.
// C4378_b.cpp
// compile with: /clr
#pragma warning(disable:4378)
using namespace System;
typedef void (__cdecl *PF)(void);
typedef void (__clrcall * CLRPF)(void);
int cxpf = 0; // number of destructors we need to call
PF pfx[200]; // ptrs to those dtors. Watch out for overflow!
ref class TypeClassHolder {
public:
static TypeClassHolder ^typeClass = gcnew TypeClassHolder();
};
CLRPF FuncTokenToFuncPtr(PF tknFunc) {
ModuleHandle type =
Type::GetTypeFromHandle(Type::GetTypeHandle(TypeClassHolder::typeClass))->Module->ModuleHandle;
return (CLRPF)type.ResolveMethodHandle((int)(size_t)(tknFunc)).GetFunctionPointer().ToPointer();
}
int myexit (PF pf) {
pfx[cxpf++] = pf;
return 0;
}
struct A {
A() {}
~A() {}
};
A aaaa;
#pragma data_seg(".mine$a")
PF InitSegStart = (PF)1;
#pragma data_seg(".mine$z")
PF InitSegEnd = (PF)1;
#pragma data_seg()
void InitializeObjects () {
PF *x = &InitSegStart;
for (++x ; x < &InitSegEnd ; ++x)
if(*x) {
CLRPF realppfunc;
realppfunc = FuncTokenToFuncPtr(*x);
(realppfunc)();
}
}
#pragma init_seg(".mine$m",myexit)
A bbbb; // constructor call succeeds
int main () {
InitializeObjects();
}
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