Thread: Help with pointers and a function

It is just a pointer, in the end, so:

Code:

*ptr = *G_PTR;

Originally Posted by newbie30

Right i have the following:

Code:

char *G_PTR = NULL   //its a global

in a module i have this

char * ptr
func(&ptr)

void func (char *ptr);
{

      //lets say G_PTR has been assigned some values
     //so how do i assign the value in G_PTR to ptr?
    //tried  different options
    *ptr = G_PTR
      ptr = G_PTR
}

Thanks

The *(related to pointer) operator is the "value at address" operator. So, whenever there is a pointer then you can use the * operator to find the value at the address pointed to by the pointer.

Originally Posted by newbie30

Code:

      //lets say G_PTR has been assigned some values
     //so how do i assign the value in G_PTR to ptr?
    //tried  different options

I would be slightly suspicious of laserlight's method if this char* pointer refers to a string. In that case, to copy the value you will need to assign memory to ptr and use strcpy. If you just want them to point to the same data:

ptr = G_PTR;

is fine, but beware changes to the data (via either of the pointers) will obviously mean that data is also changed for the other one.

You need to be a bit more particular about what you are trying to do.

Originally Posted by MK27

I would be slightly suspicious of laserlight's method if this char* pointer refers to a string. In that case, to copy the value you will need to assign memory to ptr and use strcpy.

Good point. However...

Originally Posted by MK27

If you just want them to point to the same data:

ptr = G_PTR;

is fine

Yes, but it is also useless, since ptr will go out of scope immediately afterwards.

Originally Posted by laserlight

Yes, but it is also useless, since ptr will go out of scope immediately afterwards.

Yeah, it's not really clear why the OP wants or needs to use a GLOBAL pointer this way, unless s/he has misunderstood something about global scope.