Qt-interest Archive, December 2006
O_EXCL
Message 1 in thread
Is there support for something similar to O_EXCL for QFiles? I.e. I want
to open a file for writing. If the file exists already QFile::open()
must fail.
Any hints?
/eno
--
[ signature omitted ]
Message 2 in thread
On 12/19/06, Enrico Thierbach <troll@xxxxxxxxxxxx> wrote:
> Is there support for something similar to O_EXCL for QFiles? I.e. I want
> to open a file for writing. If the file exists already QFile::open()
> must fail.
Doesn't seem like it. Is QFile::exists() an option?
--
[ signature omitted ]
Message 3 in thread
Robin Ericsson wrote:
> On 12/19/06, Enrico Thierbach <troll@xxxxxxxxxxxx> wrote:
>> Is there support for something similar to O_EXCL for QFiles? I.e. I want
>> to open a file for writing. If the file exists already QFile::open()
>> must fail.
>
> Doesn't seem like it. Is QFile::exists() an option?
No, because it's not atomic.
/eno
--
[ signature omitted ]
Message 4 in thread
On Dec 19, 2006, at 8:54 AM, Enrico Thierbach wrote:
> Is there support for something similar to O_EXCL for QFiles? I.e. I
> want to open a file for writing. If the file exists already
> QFile::open() must fail.
>
> Any hints?
Use Unix ::open() with the appropriate flags, and pass the file
descriptor to QFile;:open( int, OpenMode ). I would expect QFile::open
() to return false if the given file descriptor is -1, which is the
case when ::open() fails. The only bummer is that in this mode
QFile::close() does not actual close a valid file descriptor; you
will have to derive from QFile to do this.
Brad
--
[ signature omitted ]
Message 5 in thread
Brad Howes wrote:
> On Dec 19, 2006, at 8:54 AM, Enrico Thierbach wrote:
>
>> Is there support for something similar to O_EXCL for QFiles? I.e. I
>> want to open a file for writing. If the file exists already
>> QFile::open() must fail.
>>
>> Any hints?
>
> Use Unix ::open() with the appropriate flags, and pass the file
> descriptor to QFile;:open( int, OpenMode ). I would expect QFile::open()
> to return false if the given file descriptor is -1, which is the case
> when ::open() fails. The only bummer is that in this mode QFile::close()
> does not actual close a valid file descriptor; you will have to derive
> from QFile to do this.
>
> Brad
>
That's it! Thanks,
/eno
--
[ signature omitted ]
