I have this function in my Go project and I am getting the error as:
undefined syscall.Mmap
func memMap(fd uintptr, base int64) (mem []uint32, mem8 []byte, err error) {
mem8, err = syscall.Mmap(
int(fd),
base,
memLength,
syscall.PROT_READ|syscall.PROT_WRITE,
syscall.MAP_SHARED,
)
if err != nil {
return
}
// Convert mapped byte memory to unsafe []uint32 pointer, adjust length as needed
header := *(*reflect.SliceHeader)(unsafe.Pointer(&mem8))
header.Len /= (32 / 8) // (32 bit = 4 bytes)
header.Cap /= (32 / 8)
mem = *(*[]uint32)(unsafe.Pointer(&header))
return
}
Windows does not have the mmap(2) syscall—it's POSIX-specific (just in case: what "POSIX" is).
Windows has MapViewOfFile() and friends.
There are two approaches, I reckon:
Use a "wrapper" package such as golang.org/x/exp/mmap which tries to provide a generic memory-mapping API which is cross-platform (that is, on POSIX platforms it will use mmap(2) and on Windows is will use Windows-specific API).
Use the appropriate Win32 API functions directly instead of syscall.Mmap.
Should you take this route, the golang.org/x/sys/windows package has the relevant functions readily available.
A third approach is to have your own custom implementation working with memory-mapped data which calls either syscall.Mmap and friends of Windows-specific API. Such implementation should supposedly involve using so-called build constraints to conditionally compile a particular target platform-specific implementation—just like golang.org/x/exp/mmap does.