Fabiano Sidler wrote: > 2006/3/14, Fabiano Sidler <[EMAIL PROTECTED]>: >>Ok, sorry! I wanted to do this: >> >>--- snip --- >>from mmap import mmap, MAP_ANONYMOUS >>mm = mmap(-1, 1024, MAP_ANONYMOUS) >>--- snap --- >> >>But I got an EnvironmentError, "[Errno 22] Invalid argument" (on >>Linux2.6, btw.). The reason why I want to use anonymous mapping is >>that it only allocates the memory it actually uses. > > Hello? Nobody out there who can answer this question?
From the Linux mmap(2) man page: http://www.die.net/doc/linux/man/man2/mmap.2.html "You must specify exactly one of MAP_SHARED and MAP_PRIVATE." From the /usr/include/bits/mman.h: /* Sharing types (must choose one and only one of these). */ #define MAP_SHARED 0x01 /* Share changes. */ #define MAP_PRIVATE 0x02 /* Changes are private. */ /* ... later ... */ # define MAP_ANONYMOUS 0x20 /* Don't use a file. */ # define MAP_ANON MAP_ANONYMOUS The problem is that python mmap defaults to MAP_SHARED, but when you pass in (only) MAP_ANONYMOUS as the access parameter, you are silently unsetting the MAP_SHARED bit and not setting the MAP_PRIVATE bit. Linux wants to know which you want. With Python 2.4 on Linux 2.6, both work: from mmap import mmap, MAP_ANONYMOUS, MAP_SHARED, MAP_PRIVATE m1 = mmap(-1, 1024, MAP_ANONYMOUS|MAP_PRIVATE) # no error m2 = mmap(-1, 1024, MAP_ANONYMOUS|MAP_SHARED) # no error -- Ben Caradoc-Davies <[EMAIL PROTECTED]> http://wintersun.org/ "Those who deny freedom to others deserve it not for themselves." - Abraham Lincoln -- http://mail.python.org/mailman/listinfo/python-list
