Support for Windows.

[cshanjib]

Worked well with Unix and Darwin. Need a support for windows as well.

[rosunshrestha]

Similar issue with me. I think this is an issue with dependency offheap uses. https://github.com/tysonmote/gommap/pull/3/files
This might be the case what you are looking for. But it need to be tested,

[glycerine]

I welcome PRs to improve portability.

[cshanjib]

I went through the pull request https://github.com/tysonmote/gommap/pull/3/files which claims the support for the windows of gommap. I tried it and again got stucked in the offheap/malloc.go.
Here is the log if anybody could help,

..\..\..\..\github.com\glycerine\offheap\malloc.go:41:30: cannot use int(mm.File.Fd()) (type int) as type syscall.Handle in argument to syscall.Ftruncate
..\..\..\..\github.com\glycerine\offheap\malloc.go:81:11: undefined: syscall.MAP_SHARED
..\..\..\..\github.com\glycerine\offheap\malloc.go:83:11: undefined: syscall.MAP_ANON
..\..\..\..\github.com\glycerine\offheap\malloc.go:83:30: undefined: syscall.MAP_PRIVATE
..\..\..\..\github.com\glycerine\offheap\malloc.go:117:13: undefined: syscall.Stat_t
..\..\..\..\github.com\glycerine\offheap\malloc.go:118:14: undefined: syscall.Fstat
..\..\..\..\github.com\glycerine\offheap\malloc.go:125:31: cannot use mm.Fd (type int) as type syscall.Handle in argument to syscall.Ftruncate
..\..\..\..\github.com\glycerine\offheap\malloc.go:136:10: undefined: syscall.PROT_READ
..\..\..\..\github.com\glycerine\offheap\malloc.go:136:30: undefined: syscall.PROT_WRITE
..\..\..\..\github.com\glycerine\offheap\malloc.go:144:11: undefined: syscall.MAP_ANON
..\..\..\..\github.com\glycerine\offheap\malloc.go:144:11: too many errors

[glycerine]

consts_win.go defines the MAP_SHARED, etc; so we just need a consts_posix.go that does the same and then have malloc.go use those constants instead of the syscall ones that vary between OS.

The int vs syscall.Handle looks like a conversion problem that should be easy to solve by looking at the expected signature of Ftruncate, and converting to the correct type.

[exapsy]

syscall is not specific to Windows. So, in malloc.go you would need a malloc_unix and a malloc_windows most likely, each with their corresponding

//go:build windows

or

//go:build darwin || dragonfly || freebsd || linux || nacl || netbsd || openbsd || solaris

You would have to have different implementations as well, since POSIX systems use flags such as these

		syscall.PROT_READ|syscall.PROT_WRITE,
		syscall.MAP_ANONYMOUS|syscall.MAP_PRIVATE,

while windows uses more like these

	kernel32 := windows.NewLazySystemDLL("kernel32.dll")
	virtualAlloc := kernel32.NewProc("VirtualAlloc")

	r1, _, err := virtualAlloc.Call(
		0,
		size,
		uintptr(0x1000), // MEM_COMMIT
		uintptr(0x04),   // PAGE_READWRITE
	)

In general, that's how I'm implementing, my incomplete for now, memory allocator. Separate implementations for the syscalls for separate systems, as mmap is specific to POSIX.