Re: ifstream and empty strings

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From: Nikola Dudar [MSFT] (nikolad_at_online.microsoft.com)
Date: 01/07/05 

Date: Thu, 6 Jan 2005 18:36:35 -0800

This has been fixed in VS2005. Now ifstream does return a null stream for
"". Also fopen("") does not assert anymore and returns null file handler and
sets errno to EINVAL to inform about invalid parameter passed to fopen().

Thanks,
Nikola 

-- 
Nikola Dudar
Visual C++ Team
This posting is provided "AS IS" with no warranties, and confers no rights.
"Duane Hebert" <spoo@flarn.com> wrote in message 
news:egXGAG$8EHA.2540@TK2MSFTNGP09.phx.gbl...
>
> "Tom Widmer" <tom_usenet@hotmail.com> wrote in message news:%
>
>> sb.open has to behave "as-if" it calls fopen, so the real question is
>> whether fopen can assert here. The C standard doesn't really explicitly
>> say what should happen if an invalid file name is passed to fopen, but I
>> suspect that it's undefined behaviour. What makes a valid file name is
>> implementation defined of course, and in Windows an empty string is
>> clearly an invalid file name.
>
> That's most likely what's happening but I found it odd.
> ifstream() should be returning a null stream and setting
> the error bit when it fails to open a file.  It would seem that
> an invalid filename should trigger the same thing.  I've
> added this test in functions where I'm using it but I
> found it odd.
>
> FWIW I'm porting stuff from BCB/VCL to
> MSVC/Qt and both Borland's BCB6 and Qt seem to
> handle this.
>
>