Re: [boost] [context] Linux x64 / printf

Subject: Re: [boost] [context] Linux x64 / printf
From: Daniel Larimer (dlarimer_at_[hidden])
Date: 2012-09-11 20:27:36

On Sep 11, 2012, at 12:56 PM, Oliver Kowalke <oliver.kowalke_at_[hidden]> wrote:

> Am 11.09.2012 18:14, schrieb Daniel Larimer:
>> On Tue, Sep 11, 2012 at 1:57 AM, Pekka Seppänen <
>> pekka.seppanen_at_[hidden]> wrote:
>> 
>>> On 11.9.2012 5:00, Daniel Larimer wrote:
>>>> I modified the 'jump.cpp' example and added the line marked CRASH in f1()
>>>> 
>>>> #include <cstdlib>
>>>> #include <cstring>
>>>> #include <iostream>
>>>> #include <vector>
>>>> 
>>> ...
>>> 
>>>> void f1( intptr_t)
>>>> {
>>>>       std::cout<<"hello "<<0;  // WORKS
>>>>       printf( "hello %d", 0 ); // <<< CRASH
>>>>       std::cout << "f1: entered" << std::endl;
>>>>       std::cout << "f1: call jump_fcontext( & fc1, & fc2, 0)" <<
>>> std::endl;
>>>>       ctx::jump_fcontext( & fc1, & fc2, 0);
>>>>       std::cout << "f1: return" << std::endl;
>>>>       ctx::jump_fcontext( & fc1, & fcm, 0);
>>>> }
>>> I guess printf should be pulled from cstdio (not that you should use it,
>>> printf that is, in the first place), so perhaps your compiler is using some
>>> short of build-in instead which causes the crash.
>>> 
>>   I am just using the standard compiler... the reason I was using printf()
>> is because I wanted to avoid including all of iostream in every build...
>> accelerate compile times.
>> 
>>   Fortunately, I wrap all of my console prints in a debug macro that made
>> it easy for me to switch to iostream at the expense of doubling my compile
>> times.
>> 
>>   If it were simply a 'stack size' issue then it still wouldn't solve my
>> problem because I really to do want the minimum stack size as I have a lot
>> of async operations where the state is managed on the 'stack'.
>> 
>> 
> your app does not crash (cstdio must be included) on my x86_64 Linux system
> 
   You are right, printf() does not crash, but fprintf( stderr, "hello %d", 0 ) does seem to crash... I simplified it too much for the bug report.  To be fair, fprintf( stdout, "hello %d", 0 ) also works... so it appears to only be stderr that is crashing.
 
   Using fprintf( stderr, "..." ) in main works just fine, it is only from the context of f1() that there is a problem.

> _______________________________________________
> Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost