CODEWITHSUNDEEP
gommap
Rio
Rio

Reputation: 1918

How do you Mmap() a file bigger than 2GB in Go?

The syscall.Mmap() call takes a length argument of type int, which is only good for 2GB. How do I mmap a bigger file then?

Note: 64-bit system, so address space is not a problem.

Upvotes: 0

Views: 1941

Answers (1)

dsymonds
dsymonds

Reputation: 857

Look in http://golang.org/src/pkg/syscall/syscall_unix.go at the Mmap method on mmapper. You should be able to copy that code and adapt it as required.

Of course you won't be able to mmap to a []byte, since slice lengths are defined to be "int" (which is 32-bit everywhere at the moment). You could mmap to a larger element type (e.g. []int32), or just muck with the pointer to the memory, but it won't be a drop-in replacement to syscall.Mmap.

Upvotes: 4

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