Reading memory into a string causes program crash?

[h4344]

Im trying to read a memory address that contains text.

However when i do

if(!ReadProcessMemory(hprocess,(void *)0x0000000,(void *)&datakey.race1,sizeof(datakey.race1),0)){
            datakey.race1[] = "Non";
}

My program just crashes on startup

The array in my struct is

char race1[3];

I have no idea what im doing here since i rarely use "char". But pretty much im just trying to get the data from that memory address into a string variable. (The actual address is different from all zero's)

[webJose]

You are trying to read memory address zero, and that's illegal. See http://msdn.microsoft.com/en-us/library/windows/desktop/ms680553(v=vs.85).aspx for proper usage of the ReadProcessMemory() function.

[andywestken]

#1 This

My program just crashes on startup

makes is sound like your program crashes immediately after launch. Before it could have gotten to your code. I take it this is not the case?

#2 If you want to set a char buffer to "Non" then you need

memcpy(datakey.race1, "Non", 3);

or

datakey.race1[0] = 'N';
datakey.race1[1] = 'o';
datakey.race1[2] = 'n';

Note: that if you want to display "Non" as a C-string, you need to add space for a null terminator. And then you can use strcpy() instead of memcpy()

#3 Is the string you're trying to copy null terminated?

Andy

PS changing the example address to something other than zero might space some confusion? or use a variable (e.g. mem_addr?)

[Computergeek01]

If "datakey.race1" is an array then you shouldn't have to pass it by reference. This function only needs a pointer that is cast to void, not a pointer to a pointer.

[andywestken]

@Computergeek01

Isn't it the address-of operator in this context, rather than a reference?

[Computergeek01]

@ andywestken: Yeah, it would mean the OP is passing the pointer to the pointer of the beginning of the array. Did I write that wrong? It's one of those things I have trouble putting into words. The OP still needs to delete it right?

[andywestken]

Write it wrong? No.

I don't think delete is needed here. ReadProcessMemory will copy into the memory provided (the 3 bytes in the race1 array) if the & is lost (or &datakey.race1[0] is used)

But I think you're right that the address is needed rather than the address of the address.