C.struct_Mem larger than address space

[SuperGod]

I get this error information when build go-sqlite3 on windows use go of i386,both go1.4 and go 1.5

.\callback.go:31: type [1073741824]*C.struct_Mem larger than address space
.\callback.go:31: type [1073741824]*C.struct_Mem too large
.\callback.go:38: type [1073741824]*C.struct_Mem larger than address space
.\callback.go:38: type [1073741824]*C.struct_Mem too large

[mattn]

could you please show me the code?

[SuperGod]

I just run this command：

go get -u github.com/mattn/go-sqlite3

and then get this error information.

maybe this code is error?

func callbackTrampoline(ctx *C.sqlite3_context, argc int, argv **C.sqlite3_value) {
    args := (*[1 << 30]*C.sqlite3_value)(unsafe.Pointer(argv))[:argc:argc]
    fi := (*functionInfo)(unsafe.Pointer(C.sqlite3_user_data(ctx)))
    fi.Call(ctx, args)
}

1 << 30 is 1073741824.
when I change "1<<30" to "1<<20",then no errors.
so I think maybe "1 << 30 " is to large in 32bit platform

[mattn]

Ah, overflow. I'll fix.

[mattn]

@SuperGod could you please try below?

package main

func main() {
    if false {
        a := 1 << 30
        println(a)
    }
}

[SuperGod]

nothing print, My go version:

go version go1.5.1 windows/386

[mattn]

callbackTrampoline is not called with go get, i think.

[SuperGod]

Maybe this example will help you:

package main

import (
    "fmt"
)

func main(){
    var array [1<<30]int
    fmt.Println(len(array))
}

build this code,I get this errors:

.\array.go:8: type [1073741824]int larger than address space
.\array.go:8: type [1073741824]int too large

The type of "int" take 4 Byte memory,so the max slice/array length will be MaxUnit/sizeof(int) or MaxInt/sizeof(int)

[SuperGod]

this code build with no errors.

package main

import (
    "fmt"
    "math"
)

func main(){
    var array [math.MaxInt32-1]byte
    fmt.Println(len(array))
}

but this code will cause error:

package main

import (
    "fmt"
    "math"
)
type a struct{
}
func main(){
    var array [math.MaxInt32-1]*a
    fmt.Println(len(array))
}

error:

.\array.go:10: type [2147483646]*a larger than address space
.\array.go:10: type [2147483646]*a too large

because the point of struct may also take 4 Byte memory at i386.

[mattn]

Thank you

[mattn]

Ah math.MaxInt32 is const. it's better. I'll fix.

[SuperGod]

I am sorry your code is also error.
this code maybe the right way:

//export callbackTrampoline
func callbackTrampoline(ctx *C.sqlite3_context, argc int, argv **C.sqlite3_value) {
    var temp *C.sqlite3_value
    args := (*[(math.MaxInt32 - 1)/unsafe.Sizeof(temp)]*C.sqlite3_value)(unsafe.Pointer(argv))[:argc:argc]
    fi := (*functionInfo)(unsafe.Pointer(C.sqlite3_user_data(ctx)))
    fi.Call(ctx, args)
}

//export stepTrampoline
func stepTrampoline(ctx *C.sqlite3_context, argc int, argv **C.sqlite3_value) {
    var temp *C.sqlite3_value
    args := (*[(math.MaxInt32 - 1)/unsafe.Sizeof(temp)]*C.sqlite3_value)(unsafe.Pointer(argv))[:argc:argc]
    ai := (*aggInfo)(unsafe.Pointer(C.sqlite3_user_data(ctx)))
    ai.Step(ctx, args)
}

[mattn]

make sense.