eCos uSTL 1.3 port for review

[Jonathan Larmour]

Sergei Gavrikov wrote:
> Uwe
> 
> Today when I do re-test all from scratch (ustl build on synthetic), I
> found that this patch does not work. It seems that I ran in false clean
> up.  The previous tweak:
> 
>     virtual ~Cyg_VsnprintfStream() { /* *s_ = '\0'; */ }
> 
> works only. I cannot know why this assignment
> 
>     *s_ = '\0';
> 
> there :-(
> 
> So, such the desctuctor (the below) works for synthetic ustl build
> 
>     virtual ~Cyg_VsnprintfStream() {}
> 
> I'm sorry about. It seems we should ask Jonathan Larmour about this
> terminator.

I don't believe vfnprintf() adds trailing null terminators in its output, 
but the string needs one, so this is how it's added. Otherwise you are 
gambling on the memory pointed to by the string already having NULLs in. I 
suspect when you've had this working, that has happened to be the case.

I think I know what the real problem is - if the string is truncated, the 
NULL will be placed after the "size" argument. Please try the attached 
untested patch (not yet committed).

Jifl

> On Thu, Aug 06, 2009 at 04:56:03PM +0300, Sergei Gavrikov wrote:
> 
>>On Thu, Aug 06, 2009 at 04:25:11PM +0300, Sergei Gavrikov wrote:
>>
>>>On Thu, Aug 06, 2009 at 03:44:16PM +0300, Sergei Gavrikov wrote:
>>>
>>>>Uwe Kindler wrote:
>>>>
>>>>>It would be really great, If you could investigate a little bit more, 
>>>>>what causes the SIGSEG for synthetic target. Would you be so kind to run 
>>>>>the new snprintf_c99.c test on synthetic target when C99 compliance 
>>>>>activated to check if my vfnprintf() patch is working properly?
>>>>
>>>> 
>>>>Uwe, 
>>>>
>>>>snprintf_c99 test passed successfully on synth. It seems that I should
>>>>grep all  #if linux in ustl and look on that. I will try to rebuild ustl
>>>>with assertions and will try to re-run the tests. I'll let you know what
>>>>I will get then.
>>>
>>>Hm, Uwe, SIGSEG occured on a call of a destructor in vsnprintf.cxx (it's
>>>not your source). The uSTL test run on synthetic target with this dirty
>>>tweak. Do you have any thoughts?
>>
>> 
>>With this patch both set of tests libc/stdio and cxx/ustl passed
>>successfully on synthetic target.
>>
>>Sergei
> 
> 
>>Index: vsnprintf.cxx
>>===================================================================
>>RCS file: /cvs/ecos/ecos/packages/language/c/libc/stdio/current/src/common/vsnprintf.cxx,v
>>retrieving revision 1.6
>>diff -u -r1.6 vsnprintf.cxx
>>--- vsnprintf.cxx	29 Jan 2009 17:49:53 -0000	1.6
>>+++ vsnprintf.cxx	6 Aug 2009 13:49:24 -0000
>>@@ -71,7 +71,7 @@
>> public:
>>     Cyg_VsnprintfStream(char* s): s_(s) {}
>> 
>>-    virtual ~Cyg_VsnprintfStream() { *s_ = '\0'; }
>>+    virtual ~Cyg_VsnprintfStream() { if (s_) *s_ = '\0'; }
>> 
>>     virtual Cyg_ErrNo write( const cyg_uint8 *buffer,
>>         cyg_ucount32 buffer_length, cyg_ucount32 *bytes_written );
> 
> 
> 
> 


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