Using void*

**BloodshedDude** · 11-20-2005

I'm trying to run the following code but it's not compiling. What am I doing wrong?

Code:

void func(void* ptr)
{
	static_cast<char*>(ptr);
	cout << ptr[0];
}

**sunnypalsingh** · 11-20-2005

Try This...this will compile...but at runtime it will most probably fail..because trying to access uninitialised ptr

Code:

void *ptr;
	char *p;
	p=static_cast<char*>(ptr);
	cout << p[0];

**BloodshedDude** · 11-20-2005

Thanks. Your post pointed out my problem. Here is the code:

Code:

 void func(void* ptr, int numbytes, char value)
{
static_cast<char*>(ptr);
cout << static_cast<char*>(ptr)[i];
}

**Daved** · 11-20-2005

There is no need for the first line in your function. A static_cast (or any other cast) doesn't modify the variable you pass to it, it returns the casted variable. So to get it to work, you need to save the return value like sunnypalsingh did, or use the return value like the second line in your function does. If you do neither, the cast has no effect, which is why your first line is useless.

**BloodshedDude** · 11-20-2005

Originally Posted by Daved

There is no need for the first line in your function. A static_cast (or any other cast) doesn't modify the variable you pass to it, it returns the casted variable. So to get it to work, you need to save the return value like sunnypalsingh did, or use the return value like the second line in your function does. If you do neither, the cast has no effect, which is why your first line is useless.

Oops. My mistake. Thanks for pointing that out. I had that in there for testing purposes and forgot to take it out.

Thread: Using void*

Thread Tools

Search Thread

Display

Using void*