mmap
====
:title: Shellcode Compiler Runtime

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void* mmap(void* addr, size_t len, int prot, int flags, int fd, uint64_t offset);
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Maps a block of memory of `len` bytes with page protection `prot`.  If `addr` is `NULL`, the system
automatically picks a free virtual address.  If `addr` is not `NULL`, the provided address is mapped
(existing mappings will be overridden).

The protection flags in `prot` can include one or more of `PROT_READ`, `PROT_WRITE`, and `PROT_EXEC`.

The `flags` parameter must contain one of `MAP_SHARED` or `MAP_PRIVATE`.  Additional flags include
`MAP_ANONYMOUS`, which maps a region backed by RAM instead of a file.  The `fd` parameter should be
`-1` when mapping anonymous pages.  If the region is to be backed by a file, the `fd` and `offset`
parameters specify the file handle and offset within the file of the beginning of the mapping.

Returns a pointer to the mapped region.

See also
--------
link:munmap.html[munmap]