Better way of handling the global char array in c++.

[pdk5]

I have the following defined in the .h.
static const char *pszPath = "\\stemp\\new\\example";

I want to change to global in the dll, so it can be changed in the various functions.
What is the best way to do this, and how do I take care of deleting this memory

change to :
extern const char *pszPath = "\\stemp\\new\\example";

file1.cpp
{
string out = "temp";

pszModelParams = (char *)malloc(sizeof(out));


memcpy(pszModelParams, out.c_str(), sizeof(out));

int x = 0;


}

file2()
{

}


main()
{

// delete pointer here
}

[2kaud]

Memory should be allocated/deleted in the same .exe/.dll. So if a certain .dll allocates the memory, the same .dll should delete it. The allocated pointer can be passed and used in the .exe and other .dlls but only the creator should delete it. You don't have 'global in the .dll'. You have a .dll function that allocates/sets the memory which returns a pointer. You then have another .dll function which takes the allocated memory pointer and deletes it. Note that the initial allocation/initialisation can be done in the .dll's DLL_PROCESS_ATTACH notification. Then the .dll function just returns the required pointer.

[pdk5]

Thanks for the answer kaud.

In my case, the gloal pointer is used only within functions of my dll only. So i need to take care of allocation and deletion.

Now my Q is regarding the better way of implementing the global char array.

I set this variable when a call to certain function within my dll calls it. And when another function from my dll is called, this global is used there within my function

As it is char *, i need to allocate the memory in function1, and on completinn of last function call in the dll, i need to delete this pointer.

What us the better way if implemeting this in c++, is it better to go for smart pointer ? Or will it be ok, if i just user char * and proceed with the kind of implentation which is almost similar to present one

[2kaud]

If it is used totally within one dll with no external exposure, why not just a simple global std::string?

[pdk5]

I prefer to keep char *, as these are passed to some functions within the tlb file and i want to retain that interface.

But in the project where i reference, these are stored as static as it is used for testing some particular value. But in my case, it cannot be static, as it is changed in runtime

i.e the example where i took it was defined like this in .h file
static char *pszPath = "\\\\temp\\New";

And interface function it was called like
m_pInteropModel->SetSpecialData(bstr_t(pszPath))


But in my case,
I moved to .cpp:
char *pszpath;

and .h :
extern char *psz;


function1()
{
malloc(pszData);
}

function2()
{
//use pszpath
}

function3
{
//delete pszpath

}

All three above functions are within my dll


Hope this is ok !

[pdk5]

Not sure why they already declared as static char *, instead of string ?

I just wanted to make it non static to be able to write in runtime , so was trying to keep the same way it is done earlier instead of changing to string.

[2kaud]

You are confusing static with const. const means it can't be changed. static has different meanings depending upon where it is used. If used with a global variable, that variable can only be used from its point of definition to the end of that compilation unit (internal linkage).

Does the .dll consist of multiple .cpp files? If it has only 1 .cpp file, why is pszpath extern (external linkage) - as you have already stated in post #3 that pszpath is used only within the .dll functions.