Programming

That is not what #3 is meant to say - that memory WAS part of a now extinct process - that is why you cannot konw the contents of memory beforehand.

Memory that came from an extinct process gets blanked before anything else gets it.

What may be different is different arrangements of the stack frame, and the like. With the compiler options you have that days (stack protectors, etc) it can vary quite a bit.

I knew about undefined memory areas.
What is confusing me is when you do some implicit definitions like

Code:

char * mystring="some text";

So, as corona said, somehow my pointers should have already been initialized to some available memory area.
And this has consistently been the case on a single machine.
It consistently wasn't on another two machines.

Um, no. I was telling you that what you were doing is wrong, not that what you were doing ought to work.

Let me put it this way.

"some text" becomes valid memory when compiled. That text has to get into the program somehow, right? (It's unwritable memory, fyi, so if you try and edit it you'll get a surprise.) It's not an implicit strcpy. The memory already exists and will exist for the entire duration of the program. You do not need to copy the string to have it.

The pointer itself, though? Until you make it point to anything valid, can point to valid or invalid memory, depending wholly on chance and undefined things.

So lets compare your two methods of assignment:

Code:

char *mysterymemory;
// mysterymemory points to god-knows-what when the program starts.
// Let's play memory roulette and write to god-knows-what!
// This might work, or might write 'mystring' right into the middle of my return frame,
// or even crash immediately.
strcpy(mysterymemory, "mystring");

Code:

// This pointer does not point to god-knows-what.
// This pointer points to the valid memory that "mystring" exists inside.
// The bytes "mystring" don't have to be written anywhere.
// This is not anything like strcpy.
// We are just pointing to memory that ALREADY EXISTS.
char *validmemory="mystring";