Re: [boost] [interprocess] SHARING_VIOLATION due to antivirus

Subject: Re: [boost] [interprocess] SHARING_VIOLATION due to antivirus
From: Lars Hagstrom (lars_at_[hidden])
Date: 2009-08-19 12:01:51

Yes, I quite expected Ion to move the constant to where all the other 
constants are, at the top of that file. I didn't really mean for the 
patch to go in as is (and I'm pretty sure Ion wouldn't anyway, my patch 
isn't really in the same coding style...;-)

But you are right!

Lars

Stewart, Robert wrote:
> Lars Hagstrom wrote:
>> I made a quick patch to create_file in win32_api.hpp (the patch is
>> rather verbose, to make its workings obvious):
>>
>> static inline void *create_file(const char *name, unsigned
>> long access,
>> unsigned long creation_flags, unsigned long attributes = 0)
>> {
>>      int tries = 0;
>>      for (;;)
>>      {
>>          void * const res = CreateFileA(name, access,
>>              file_share_read | file_share_write | file_share_delete,
>>              0, creation_flags, attributes, 0);
>>          if (tries > 100)
>>          {
>>              //ran out of attempts, return and let the exceptions fly
>>              return res;
>>          }
>>          if (res != invalid_handle_value)
>>          {
>>              //all went well, return
>>              return res;
>>          }
>>          else if (GetLastError() != 32)
>>          {
>>              //we got some other error than an ERROR_SHARING_VIOLATION,
>>              //let the caller handle the error.
>>              return res;
>>          }
>>
>>          Sleep(1);
>>          ++tries;
>>      }
>> }
> 
> I think this would be more readable and do the same:
> 
> static inline void *
> create_file(const char * name, unsigned long access,
>    unsigned long creation_flags, unsigned long attributes = 0)
> {
>    for (int attempt(0); attempt < 100; ++attempt)
>    {
>       void * const handle(
>          CreateFileA(name, access,
>             file_share_read | file_share_write | file_share_delete,
>             0, creation_flags, attributes, 0));
>       bool const invalid(invalid_handle_value == handle);
>       if (!invalid)
>       {
>          return handle;
>       }
>       bool const sharing_violation(32 == GetLastError());
>       if (!sharing_violation)
>       {
>          return handle;
>       }
>       Sleep(1);
>    }
>    return invalid_handle_value;
> }
> 
> This makes the magic number more obvious, too (assuming it were to remain a magic number).
> 
> _____
> Rob Stewart                           robert.stewart_at_[hidden]
> Software Engineer, Core Software      using std::disclaimer;
> Susquehanna International Group, LLP  http://www.sig.com
> 
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