mmap and MAP_FIXED

[Evgeny Stambulchik]

Sean Daley wrote:

> Read the description to lpBaseAddress again and then read the
> following comment from
> cygwin's mmap code:
> /* If a non-zero address is given, try mapping using the given address first.
>    If it fails and flags is not MAP_FIXED, try again with NULL address. */

I did. Now may I ask you in exchange to re-read my previous posts?

Again, it's a mistery to me why e.g. mmap(0x641000,...), although not 
forced to, does return the _suggested_ 0x641000 _exactly_, whereas 
mmap(0x641000,..., MAP_FIXED) fails?!

> Also, the Linux man page for mmap pretty much sums it up as follows:

mmap on Linux works flawlessly with MAP_FIXED, according to the POSIX 
requirements - i.e., as far as the address is on the page boundary. In 
cygwin, it's not the case; instead, alignment to the "granularity" of 
the mem allocations is needed. BTW, can I get this value from the Cygwin 
API or need to query Win32 directly?

Regards,

Evgeny

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