Hi,

I use metakit library, and in a call to "_open()" they use flag _O_NOINHERIT

This flag is not documented (could not find in winhelp), but it exists and is set to 128 (I made a printf). When running the code below, the file is not created. I have to remove the flag, then it works. (DigitalMars compiler (8.37) )

With MS DevStudio the flag is also set to 128 but that does not change behavior and the file is created.

I would like to know if this is a bug or if there is something I dont understand.
Thanks

-- 
Riccardo Cohen

Articque
Les Roches
37230 Fondettes
France
web = http://www.articque.com
tel: +33 02 47 49 90 49
fax: +33 02 47 49 91 49
========================================================
#include <io.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <stdio.h>
int main()
{
  printf("%d\n",_O_NOINHERIT);
  int flags = _O_BINARY | _O_NOINHERIT |  _O_RDWR ;
  int  fd = _open("d:\\zdrop\\testfile.out", flags | _O_CREAT, _S_IREAD | _S_IWRITE);
  if (fd!=1)
  {
    _write (fd,"ok",2);
    _close(fd);
  }
  char tmp[100];
  gets(tmp);
  return(0);
}

How is _open() implemented in the metakit lib? With CreateFile ? The 128 (decimal) == 80(hex) == FILE_ATTRIBUTE_NORMAL which is the only exclusive flag for the file attribute arg in CreateFile.

Arjan

Riccardo Cohen wrote:
> Hi,
> 
> I use metakit library, and in a call to "_open()" they use flag _O_NOINHERIT
> 
> This flag is not documented (could not find in winhelp), but it exists and is set to 128 (I made a printf). When running the code below, the file is not created. I have to remove the flag, then it works. (DigitalMars compiler (8.37) )
> 
> With MS DevStudio the flag is also set to 128 but that does not change behavior and the file is created.
> 
> I would like to know if this is a bug or if there is something I dont understand.
> Thanks
> 

Thanks for your quick answer.
The code is :

  int flags = _O_BINARY | _O_NOINHERIT | (mode_ > 0 ? _O_RDWR : _O_RDONLY);
  int fd = _open(fname_, flags);

I dont really understand your question. _open() is not implemented by metakit library, but by win32sdk.
The function CreateFile is not called by the metakit library.

Arjan Knepper wrote:

> How is _open() implemented in the metakit lib? With CreateFile ? The 128 (decimal) == 80(hex) == FILE_ATTRIBUTE_NORMAL which is the only exclusive flag for the file attribute arg in CreateFile.
> 
> Arjan
> 
> Riccardo Cohen wrote:
> 
>> Hi,
>>
>> I use metakit library, and in a call to "_open()" they use flag _O_NOINHERIT
>>
>> This flag is not documented (could not find in winhelp), but it exists and is set to 128 (I made a printf). When running the code below, the file is not created. I have to remove the flag, then it works. (DigitalMars compiler (8.37) )
>>
>> With MS DevStudio the flag is also set to 128 but that does not change behavior and the file is created.
>>
>> I would like to know if this is a bug or if there is something I dont understand.
>> Thanks
>>
> 

-- 
Riccardo Cohen

Articque
Les Roches
37230 Fondettes
France
web = http://www.articque.com
tel: +33 02 47 49 90 49
fax: +33 02 47 49 91 49

OK you are just using the c-runtime '_open (..)'.

Take a look at the source file which implements _open (..) in the compiler src directory. That way you can see how the _O_NOINHERIT is affecting the file open api call (which will probably use CreateFile).

I would not use the "undocumented" _O_NOINHERIT. Has problaby something to do with the HANDLE returned from CreateFile not being inheritable by child processes or threads or DuplicateHandle.

Arjan

Riccardo Cohen wrote:

> Thanks for your quick answer.
> The code is :
> 
>   int flags = _O_BINARY | _O_NOINHERIT | (mode_ > 0 ? _O_RDWR : _O_RDONLY);
>   int fd = _open(fname_, flags);
> 
> I dont really understand your question. _open() is not implemented by metakit library, but by win32sdk.
> The function CreateFile is not called by the metakit library.
> 
> Arjan Knepper wrote:
> 
>> How is _open() implemented in the metakit lib? With CreateFile ? The 128 (decimal) == 80(hex) == FILE_ATTRIBUTE_NORMAL which is the only exclusive flag for the file attribute arg in CreateFile.
>>
>> Arjan
>>
>> Riccardo Cohen wrote:
>>
>>> Hi,
>>>
>>> I use metakit library, and in a call to "_open()" they use flag _O_NOINHERIT
>>>
>>> This flag is not documented (could not find in winhelp), but it exists and is set to 128 (I made a printf). When running the code below, the file is not created. I have to remove the flag, then it works. (DigitalMars compiler (8.37) )
>>>
>>> With MS DevStudio the flag is also set to 128 but that does not change behavior and the file is created.
>>>
>>> I would like to know if this is a bug or if there is something I dont understand.
>>> Thanks
>>>
>>
> 

I found that _open() function is defined as open(), but could not find open() except in IOS/FILESYS.H definition.
Anyway I understand that this undocumented flag should not be used.
Thanks for the info.

Arjan Knepper wrote:

> OK you are just using the c-runtime '_open (..)'.
> 
> Take a look at the source file which implements _open (..) in the compiler src directory. That way you can see how the _O_NOINHERIT is affecting the file open api call (which will probably use CreateFile).
> 
> I would not use the "undocumented" _O_NOINHERIT. Has problaby something to do with the HANDLE returned from CreateFile not being inheritable by child processes or threads or DuplicateHandle.
> 
> Arjan
> 
> Riccardo Cohen wrote:
> 
>> Thanks for your quick answer.
>> The code is :
>>
>>   int flags = _O_BINARY | _O_NOINHERIT | (mode_ > 0 ? _O_RDWR : _O_RDONLY);
>>   int fd = _open(fname_, flags);
>>
>> I dont really understand your question. _open() is not implemented by metakit library, but by win32sdk.
>> The function CreateFile is not called by the metakit library.
>>
>> Arjan Knepper wrote:
>>
>>> How is _open() implemented in the metakit lib? With CreateFile ? The 128 (decimal) == 80(hex) == FILE_ATTRIBUTE_NORMAL which is the only exclusive flag for the file attribute arg in CreateFile.
>>>
>>> Arjan
>>>
>>> Riccardo Cohen wrote:
>>>
>>>> Hi,
>>>>
>>>> I use metakit library, and in a call to "_open()" they use flag _O_NOINHERIT
>>>>
>>>> This flag is not documented (could not find in winhelp), but it exists and is set to 128 (I made a printf). When running the code below, the file is not created. I have to remove the flag, then it works. (DigitalMars compiler (8.37) )
>>>>
>>>> With MS DevStudio the flag is also set to 128 but that does not change behavior and the file is created.
>>>>
>>>> I would like to know if this is a bug or if there is something I dont understand.
>>>> Thanks
>>>>
>>>
>>
> 

-- 
Riccardo Cohen

Articque
Les Roches
37230 Fondettes
France
web = http://www.articque.com
tel: +33 02 47 49 90 49
fax: +33 02 47 49 91 49