On Jul 1 17:33, David Allsopp wrote:
> This program fails at the second mmap call with EINVAL:
>
> #include <stdio.h>
> #include <sys/mman.h>
> #include <error.h>
>
> int main (void) {
> void * mem;
> /* Reserve 256MB address space for the minor heaps */
> mem = mmap(0, 268439552, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
> if (mem == MAP_FAILED)
> error(1, 0, "Reservation failed");
> /* Commit the first 2MB heap */
> if (mmap(mem, 2097152, PROT_READ | PROT_WRITE, MAP_PRIVATE |
> MAP_ANONYMOUS | MAP_FIXED, -1, 0) == MAP_FAILED)
> error(1, 0, "Commit failed");
> }
>
> Is this something that's expected to fail for Cygwin, or a bug?
Depends on the point of view, I guess. PROT_NONE pages are not just
reserved pages in the Windows sense. mmap'ed pages are always commited
and PROT_NONE is just a page protection. Using mmap to change the page
protection of already commited memory is not implemented. To change
this, use mprotect.
Corinna
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