Incorrect behavior of AttachConsole (WIN32 API function) using Syscall (using Cgo is OK)

[Pavel Korotkov]

Hi gophers,

I noticed incorrect behavior of function AttachConsole in the code attached when using syscall.FindProc(...) - ....Call(...) approach. While, Cgo version works as expected (see files).
Test bench OSes: Windows 7 Professional x86-64 and Windows 8.1 Enterprise x86-64.
Could you please help me track the problem in my code? Any open issue, maybe?

Thanks in advance

Best regards,
PK

[brainman]

On Thursday, 31 October 2013 08:47:43 UTC+11, Pavel Korotkov wrote:

> ... I noticed incorrect behavior ...

Tell us about that. Tell us what your problem is. Thank you.

Alex

[brainman]

On Thu, Oct 31, 2013 at 9:50 AM, Pavel Korotkov <...> wrote:

>

> Well, I've got two AllocConsole wrappers:

>

> package main

>

> /*

> #define _WIN32_WINNT 0x0502

> #include <windows.h>

> */

> import "C"

>

> ...

>

> func AttachConsoleToParentProcess1_WINAPI() error {

>     funName := "AttachConsole"

>

>     r, err := C.AttachConsole(C.ATTACH_PARENT_PROCESS)

>     if r == 0 {

>         return fmt.Errorf(funName+"'s return flag is FALSE; Last error: %s", err.Error())

>     }

>     return nil

> }

>

> func AttachConsoleToParentProcess2_WINAPI() error {

>     funName := "AttachConsole"

>     fun, err := kernel32.FindProc(funName)

>     if err != nil {

>         return err

>     }

>

>     var app uint32 = 0xFFFFFFFF // Constant ATTACH_PARENT_PROCESS as stated in MSDN: (DWORD)-1

>     r, _, lastErr := fun.Call(uintptr(unsafe.Pointer(&app)))

>     if r == 0 {

>         return fmt.Errorf(funName+"'s return flag is FALSE; Last error: %s", lastErr.Error())

>     }

>

>     return nil

> }

>

> When I try to attach a console back to the parent process (main.go:55), only AttachConsoleToParentProcess1_WINAPI does the job. AttachConsoleToParentProcess2_WINAPI doesn't work on my machines. That's it. What else can I do?

>

> PS: Since I use Win7/Win8.1 one can omit '#define _WIN32_WINNT 0x0502' directive on top of the file.

>

I am sorry, but I don't understand what "does the job" and "doesn't work" means. Perhaps, if you can give us a program, and then tell us what you see when the program runs, and then tell us what you think is wrong with the output you see and why. Thank you.

Alex

[brainman]

I still do not know what your problem is, but in AttachConsoleToParentProcess2_WINAPI you have a bug. You should have:

r, _, lastErr := fun.Call(uintptr(app))

not

r, _, lastErr := fun.Call(uintptr(unsafe.Pointer(&app)))

Alex

[Pavel Korotkov]

Hi Alex

I was just about to describe the problem in detail... but you've already find the bug! Thank you very much!

On Thu, Oct 31, 2013 at 6:01 AM, brainman <alex.b...@gmail.com> wrote:

I still do not know what your problem is, but in AttachConsoleToParentProcess2_WINAPI you have a bug. You should have:

r, _, lastErr := fun.Call(uintptr(app))

You're right, that's an unfortunate copy-paste misprint. And this the reason why my program didn't work.

not

r, _, lastErr := fun.Call(uintptr(unsafe.Pointer(&app)))

Alex

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С уважением,

Павел Коротков