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

Subject: Re: [boost] [interprocess] SHARING_VIOLATION due to antivirus
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2009-08-19 08:30:48

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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