with no API (VirtualAlloc, HeapAlloc, etc).

Be more specific on that. Where are you supposed to get memory to allocate from? Some uninitialized section + custom allocator?

If you just want to do your own memory management you can use the end of your data section.

Then you could make your own allocate and free functions that will process and return addresses from your flat memory space. Rolling your own memory management routines will take some time and testing.

But and in the runtime? Or my app must separete a space anyway (like you shown, r22)? (I dont think so, bc if you use a HeapAlloc you dont need separete space)

baldr, I need to read some strings (file paths (unknow quantity)), And I'd like to alloc some space to store them. But I'd like to alloc the exactly size of the strings to don't spend memory.

I think the stack is the only option you have without APIs. So you'll have to use the stack for it.

Define a big stack reserve (this does not allocate memory, it only reserves address space -- make it as big as you need to, you can't have larger buffer than this!), then everytime you "touch" a 4K memory page on the stack it allocates it -- this means if you put something or access that particular stack reserved page, it gets allocated.

so conclusion:

small stack commit size, big stack reserve size.

Other than that, what's wrong with HeapAlloc?

Or using VirtualAlloc and then implementing the heap over the returned memory (which can also reserve memory space without actually occupying it in memory nor in swap file).

Teehee, also note that Windows can't allocate less than 4KB (or the page size of the system) even with HeapAlloc. Of course, HeapAlloc will use those 4KB chunks to allocate as much as possible so a single HeapAlloc of, say, 16 bytes won't deplete the entire 4KB chunk.

Nothing. I just want to know how to do that manually

Thanks for tips guys.

PS: Everything that goes in 'data section' is in heap space, right?

No. Everything that is reserved (rb, rw, rd, etc.) will not be part of the .exe, but everything that is defined (db, dw, dd, etc.) will be.


Also, from the manual:

ManOfSteel,

Not exactly. Everything uninitialized (rb/db ?) before last initialized item in section still appears in PE .Exe file, only trailing uninitialized items don't (remember file alignment though).

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Teehee,

Windows creates standard heap for process (even if you specify 0/0 as heap commit/reserve); you may use GetProcessHeap() to obtain it's handle. This heap (and any you create yourself) resides outside any sections.

From where those paths are coming? HeapAlloc() / lstrlen() / HeapReAlloc() can be quite effective.

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Borsuc,

Stack allocation has one drawback: the technique Windows uses to commit stack pages (guard pages) requires them to be touched sequentially when allocated.

Yes, that's more precise and correct than what I said and it's exactly what I meant. I was thinking of r22's post when I posted my reply.