Andrew Ross wrote: > > Hi Everyone, > > I'm interested in whether it is possible to get the size of a variable a > pointer is pointing at. > > I have a function that accepts a char * pointer. This can either be stack or > heap memory but more typically stack where I see it. > > It would help me tremendously if I could figure out the size of the variable > at the other end of the pointer. I can't think of a way to do this > unfortunately. > > strlen won't work as the variable is null when passed in > sizeof(*ptr) returns 1, even though the memory is larger > > sizeof(ptr) returns 4 (on my 32 bit machine) of course > > Can anyone think of how to do this, or am I out of luck? > This isn't a GCC question but I'll answer just the same. The only way a function can know the length of an array pointed to by a pointer is by the caller passing that information to the function. Probably the best way if you want to clear up the clutter is to use a struct which has both a pointer and length (maybe stored as an int). Tom
