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proposal: runtime/cgo: add CArray helper #58002

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tmm1 opened this issue Jan 25, 2023 · 2 comments
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proposal: runtime/cgo: add CArray helper #58002

tmm1 opened this issue Jan 25, 2023 · 2 comments
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@tmm1
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tmm1 commented Jan 25, 2023

I propose a new helper C.CArray, similar to C.CString/C.CBytes, implemented as follows:

func CArray[T any](n int) []T {
        var t T
        return (*[1 << 30]T)(C.malloc(C.size_t(n * int(unsafe.Sizeof(t)))))[:n:n]
}

I'm not quite sure what the implementation would look like inside cmd/cgo, so perhaps its better to add this method to the cgo package instead.
@tmm1 tmm1 added the Proposal label Jan 25, 2023
@gopherbot gopherbot added this to the Proposal milestone Jan 25, 2023
@bcmills
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bcmills commented Jan 25, 2023

I don't think it makes sense to have a malloc wrapper that returns a Go type instead of a C type.

Instead, push the malloc call to the caller side (where they will be prompted to consider when to free the data) and use unsafe.Slice to wrap it as a Go slice.

@tmm1
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tmm1 commented Jan 26, 2023

I don't think it makes sense to have a malloc wrapper that returns a Go type instead of a C type.

Good point, CString returns a C type.

use unsafe.Slice to wrap it as a Go slice

Thanks for this pointer, makes things much simpler.

@tmm1 tmm1 closed this as completed Jan 26, 2023
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