Re: [go-nuts] Re: How to capture stderr/stdout of cgo calls?

[Markus Zimmermann]

You are right Sebastien, I fixed that. Thanks!

On Thursday, August 4, 2016 at 6:58:06 PM UTC+2, Sebastien Binet wrote:
>
>
>
> On Thu, Aug 4, 2016 at 1:07 PM, Markus Zimmermann  > wrote:
>
>> I feared that there would be no pure Go solution. Anyway, I used fdopen 
>> variant the code is here 
>> https://github.com/zimmski/osutil/blob/master/capture.go#L51 if anyone 
>> every stumbles over this thread.
>>
>
> seems to me like you're leaking C.CString("w") at:
> https://github.com/zimmski/osutil/blob/master/capture.go#L64
>
> it's allocated from cgo so you need to:
> cw := C.CString("w")
> defer C.free(unsafe.Pointer(cw))
> // ...
>
> -s
>  
>
>>
>> Thanks for the help.
>>
>>
>> On Monday, July 25, 2016 at 1:00:46 PM UTC+2, Uli Kunitz wrote:
>>>
>>> Your program doesn't work because changing os.Stdout and os.Stdin has no 
>>> effect on stdio stdin and stdout. Stdio stdout will still reference fd 1 
>>> and stderr fd 2.
>>>  
>>> I recommend following three solutions:
>>>
>>>
>>>1. The simplest approach could be not to use cgo at all and run the 
>>>C code in a separate process. Capturing the output of a separate process 
>>> is 
>>>simple and can be done using the os/exec package.
>>>2. Reset stdin and stdout using fdopen in the C code. This could be 
>>>done permanently.
>>>3. Swap file descriptors using dup2.
>>>
>>>  
>>>  
>>>  
>>>
>> -- 
>> You received this message because you are subscribed to the Google Groups 
>> "golang-nuts" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to golang-nuts...@googlegroups.com .
>> For more options, visit https://groups.google.com/d/optout.
>>
>
>

-- 
You received this message because you are subscribed to the Google Groups 
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to golang-nuts+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[go-nuts] Re: How to capture stderr/stdout of cgo calls?

[mattn]

I guess calling freopen is better because cgo possibly having reference of 
stdin/stdout as FILE*.


On Thursday, August 4, 2016 at 8:07:40 PM UTC+9, Markus Zimmermann wrote:
>
> I feared that there would be no pure Go solution. Anyway, I used fdopen 
> variant the code is here 
> https://github.com/zimmski/osutil/blob/master/capture.go#L51 if anyone 
> every stumbles over this thread.
>
> Thanks for the help.
>
> On Monday, July 25, 2016 at 1:00:46 PM UTC+2, Uli Kunitz wrote:
>>
>> Your program doesn't work because changing os.Stdout and os.Stdin has no 
>> effect on stdio stdin and stdout. Stdio stdout will still reference fd 1 
>> and stderr fd 2.
>>  
>> I recommend following three solutions:
>>
>>
>>1. The simplest approach could be not to use cgo at all and run the C 
>>code in a separate process. Capturing the output of a separate process is 
>>simple and can be done using the os/exec package.
>>2. Reset stdin and stdout using fdopen in the C code. This could be 
>>done permanently.
>>3. Swap file descriptors using dup2.
>>
>>  
>>  
>>  
>>
>

-- 
You received this message because you are subscribed to the Google Groups 
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to golang-nuts+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.