C++ - Difference between calling a "project" function and calling a dll function

I currently have a C++ sample calling for a C++ dll function this way :

typedef BOOL(__stdcall *f_funci)(const char*, char*);

HINSTANCE hGetProcIDDLL = LoadLibrary(L"myDLL.dll");
f_funci DoSmth= (f_funci)GetProcAddress(hGetProcIDDLL, "function");

std::string test = "The cake is a lie, it's actually a Brownie...";

char *out = new char[124];
DoSmth(&test[0], out);

and the dll function prototype :

BOOL function(const char *in, char *out){}

The problem is, when i call this dll function, i got a totally random result at in[x] (whatever x value) (using visual studio debugger).

However, if i simply paste this function inside my .cpp, in[x] is always the result i would expect to have.

What i verified :

• dll function's calling convention is stdcall, as expected.
• both the sample and the dll are in the following context - Debug - x64 -

What i think it could possibly come from but don't know enough to ensure a Yes/No answer:

• memory management difference between a "simple call" and a GetProcAddress ?
• Debugger issue (would be weird considering the out value is also false in dll call case)
• Other ?

Thanks for help & time !

PS : Please consider asking for details if something is unclear !