mmap (GNU Gnulib)

Gnulib module: —

Portability problems fixed by Gnulib:

On platforms where off_t is a 32-bit type, this function may not work correctly across the entire data range of files 2 GiB and larger. See Large File Support.

Portability problems not fixed by Gnulib:

This function is missing on some platforms: mingw, MSVC 14.
To get anonymous memory, on some platforms, you can use the flags MAP_ANONYMOUS | MAP_PRIVATE and -1 instead of a file descriptor; on others you have to use a read-only file descriptor of /dev/zero.
On HP-UX, passing a non-NULL first argument, as a hint for the address (even without MAP_FIXED), often causes mmap to fail. Better pass NULL in this case.
On HP-UX, MAP_FIXED basically never works. On other platforms, it depends on the circumstances whether memory can be returned at a given address.