Native
NAME
Mmap::Native - interface to posix mmap() and mmunmap() calls
SYNOPSIS
use Mmap::Native;
my $f = $*CWD.add('META6.json'); $f = $f.open;
my $d = mmap Pointer, 50, PROT_READ, MAP_SHARED, $f.native-descriptor, 0;
my $e = blob-from-pointer $d, :50elems, :type(Buf[uint8]);
is $e.decode('utf8'), /'"auth": "zef:massa"'/;
DESCRIPTION
Mmap::Native is a raw interface to the C library mmap and munmap calls.
It's mostly used for mmaping Blob objects and other raw C pointers. It's recommended that the
library using it present a most Raku-esque interface and hide the mmapping altogether. This
is just a low level library.
CONSTANTS
Remember to always use +| to combine flag values!
### The `$prot` argument flags
Describes the desired memory protection of the mapping (and must not conflict with the open mode of the file). It is either PROT_NONE or the bitwise OR of one or more of the following flags:
| Flag | Description |
|---|
| PROT_READ | page can be read |
| PROT_WRITE | page can be written |
| PROT_EXEC | page can be executed |
| PROT_SEM | page may be used for atomic ops |
| PROT_NONE | page can not be accessed |
| PROT_GROWSDOWN | mprotect flag: extend change to start of growsdown vma |
| PROT_GROWSUP | mprotect flag: extend change to end of growsup vma |
### The `$flags` argument
Determines whether updates to the mapping are visible to other processes mapping the same region, and whether updates are carried through to the underlying file. This behavior is determined by including exactly one of the following values:
| Flag | Description |
|---|
| MAP_SHARED | Share changes |
| MAP_PRIVATE | Changes are private |
| MAP_SHARED_VALIDATE | share and validate extension flags |
| MAP_TYPE | Mask for type of mapping |
| MAP_FIXED | Interpret addr exactly |
| MAP_ANONYMOUS | don't use a file |
| MAP_GROWSDOWN | stack-like segment |
| MAP_DENYWRITE | ETXTBSY |
| MAP_EXECUTABLE | mark it as an executable |
| MAP_LOCKED | pages are locked |
| MAP_NORESERVE | don't check for reservations |
| MAP_POPULATE | populate (prefault) pagetables |
| MAP_NONBLOCK | do not block on IO |
| MAP_STACK | give out an address that is best suited for process/thread stacks |
| MAP_HUGETLB | create a huge page mapping |
| MAP_SYNC | perform synchronous page faults for the mapping |
| MAP_FIXED_NOREPLACE | MAP_FIXED which doesn't unmap underlying mapping |
| MAP_UNINITIALIZED | For anonymous mmap, memory could be * uninitialized |
| MLOCK_ONFAULT | Lock pages in range after they are faulted in, do not prefault |
| MS_ASYNC | sync memory asynchronously |
| MS_INVALIDATE | invalidate the caches |
| MS_SYNC | synchronous memory sync |
| MADV_NORMAL | no further special treatment |
| MADV_RANDOM | expect random page references |
| MADV_SEQUENTIAL | expect sequential page references |
| MADV_WILLNEED | will need these pages |
| MADV_DONTNEED | don't need these pages |
| MADV_FREE | free pages only if memory pressure |
| MADV_REMOVE | remove these pages & resources |
| MADV_DONTFORK | don't inherit across fork |
| MADV_DOFORK | do inherit across fork |
| MADV_HWPOISON | poison a page for testing |
| MADV_SOFT_OFFLINE | soft offline page for testing |
| MADV_MERGEABLE | KSM may merge identical pages |
| MADV_UNMERGEABLE | KSM may not merge identical pages |
| MADV_HUGEPAGE | Worth backing with hugepages |
| MADV_NOHUGEPAGE | Not worth backing with hugepages |
| MADV_DONTDUMP | Explicity exclude from the core dump, overrides the coredump filter bits |
| MADV_DODUMP | Clear the MADV_DONTDUMP flag |
| MADV_WIPEONFORK | Zero memory on fork, child only |
| MADV_KEEPONFORK | Undo MADV_WIPEONFORK |
| MADV_COLD | deactivate these pages |
| MADV_PAGEOUT | reclaim these pages |
| MADV_POPULATE_READ | populate (prefault) page tables readable |
| MADV_POPULATE_WRITE | populate (prefault) page tables writable |
| MADV_DONTNEED_LOCKED | like DONTNEED, but drop locked pages too |
| MADV_COLLAPSE | Synchronous hugepage collapse |
FUNCTIONS
AUTHOR
Humberto Massa `[email protected]`
COPYRIGHT AND LICENSE
Copyright Ā© 2024 Humberto Massa
This library is free software; you can redistribute it and/or modify it under either the Artistic License 2.0 or the LGPL v3.0, at your convenience.