WinAPI: wait for IO completion on a file descriptor
I write a Python app that supports Linux and Windows, and I have a file object (that has a fileno() method returning a file descriptor), and I need to wait for IO completion on it.
In this particular case it's database connection (Postgresql), and I need to process notifications without a load on CPU (like it is described here).
On Linux it's quite simple:
select.select([fd], , )
But I would like to be able to do something like that on Windows too, and I'm struggling to find the correct way to achieve it.
It looks like WaitForSingleObject function could be handy, but as far as I understand it does not accept file descriptors.
How could this possibly be resolved?
python-3.x winapi
asked Nov 23 '18 at 7:50
Ray P.Ray P.
128112
add a comment |
I write a Python app that supports Linux and Windows, and I have a file object (that has a fileno() method returning a file descriptor), and I need to wait for IO completion on it.
In this particular case it's database connection (Postgresql), and I need to process notifications without a load on CPU (like it is described here).
On Linux it's quite simple:
select.select([fd], , )
But I would like to be able to do something like that on Windows too, and I'm struggling to find the correct way to achieve it.
It looks like WaitForSingleObject function could be handy, but as far as I understand it does not accept file descriptors.
How could this possibly be resolved?
python-3.x winapi
asked Nov 23 '18 at 7:50
Ray P.Ray P.
128112
On Windows, you have to open the file usingCreateFile()specifying theFILE_FLAG_OVERLAPPEDflag, then you can create anOVERLAPPEDstruct holding a waitable event fromCreateEvent()and pass that struct to read/write operations that support overlapped I/O, then you can wait on the event. See Overlapped operations for more details. But, how you do all of that in Python, I have no clue.
– Remy Lebeau
Nov 23 '18 at 10:36
Microsofts C implementation provides functions that can transform fd's into operating system handles (_ofshandleiirc). Does Python not have a similar thing?
– Chris Becke
Nov 23 '18 at 12:01
add a comment |
I write a Python app that supports Linux and Windows, and I have a file object (that has a fileno() method returning a file descriptor), and I need to wait for IO completion on it.
In this particular case it's database connection (Postgresql), and I need to process notifications without a load on CPU (like it is described here).
On Linux it's quite simple:
select.select([fd], , )
But I would like to be able to do something like that on Windows too, and I'm struggling to find the correct way to achieve it.
It looks like WaitForSingleObject function could be handy, but as far as I understand it does not accept file descriptors.
How could this possibly be resolved?
python-3.x winapi
asked Nov 23 '18 at 7:50
Ray P.Ray P.
128112
I write a Python app that supports Linux and Windows, and I have a file object (that has a fileno() method returning a file descriptor), and I need to wait for IO completion on it.
In this particular case it's database connection (Postgresql), and I need to process notifications without a load on CPU (like it is described here).
On Linux it's quite simple:
select.select([fd], , )
But I would like to be able to do something like that on Windows too, and I'm struggling to find the correct way to achieve it.
It looks like WaitForSingleObject function could be handy, but as far as I understand it does not accept file descriptors.
How could this possibly be resolved?
python-3.x winapi
python-3.x winapi
asked Nov 23 '18 at 7:50
Ray P.Ray P.
128112
asked Nov 23 '18 at 7:50
Ray P.Ray P.
128112
asked Nov 23 '18 at 7:50
Ray P.Ray P.
128112
asked Nov 23 '18 at 7:50
Ray P.Ray P.
128112
asked Nov 23 '18 at 7:50
Ray P.Ray P.
128112
128112
On Windows, you have to open the file usingCreateFile()specifying theFILE_FLAG_OVERLAPPEDflag, then you can create anOVERLAPPEDstruct holding a waitable event fromCreateEvent()and pass that struct to read/write operations that support overlapped I/O, then you can wait on the event. See Overlapped operations for more details. But, how you do all of that in Python, I have no clue.
– Remy Lebeau
Nov 23 '18 at 10:36
Microsofts C implementation provides functions that can transform fd's into operating system handles (_ofshandleiirc). Does Python not have a similar thing?
– Chris Becke
Nov 23 '18 at 12:01
add a comment |
On Windows, you have to open the file usingCreateFile()specifying theFILE_FLAG_OVERLAPPEDflag, then you can create anOVERLAPPEDstruct holding a waitable event fromCreateEvent()and pass that struct to read/write operations that support overlapped I/O, then you can wait on the event. See Overlapped operations for more details. But, how you do all of that in Python, I have no clue.
– Remy Lebeau
Nov 23 '18 at 10:36
Microsofts C implementation provides functions that can transform fd's into operating system handles (_ofshandleiirc). Does Python not have a similar thing?
– Chris Becke
Nov 23 '18 at 12:01
On Windows, you have to open the file using
CreateFile() specifying the FILE_FLAG_OVERLAPPED flag, then you can create an OVERLAPPED struct holding a waitable event from CreateEvent() and pass that struct to read/write operations that support overlapped I/O, then you can wait on the event. See Overlapped operations for more details. But, how you do all of that in Python, I have no clue.– Remy Lebeau
Nov 23 '18 at 10:36
On Windows, you have to open the file using
CreateFile() specifying the FILE_FLAG_OVERLAPPED flag, then you can create an OVERLAPPED struct holding a waitable event from CreateEvent() and pass that struct to read/write operations that support overlapped I/O, then you can wait on the event. See Overlapped operations for more details. But, how you do all of that in Python, I have no clue.– Remy Lebeau
Nov 23 '18 at 10:36
Microsofts C implementation provides functions that can transform fd's into operating system handles (
_ofshandle iirc). Does Python not have a similar thing?– Chris Becke
Nov 23 '18 at 12:01
Microsofts C implementation provides functions that can transform fd's into operating system handles (
_ofshandle iirc). Does Python not have a similar thing?– Chris Becke
Nov 23 '18 at 12:01
add a comment |
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On Windows, you have to open the file using
CreateFile()specifying theFILE_FLAG_OVERLAPPEDflag, then you can create anOVERLAPPEDstruct holding a waitable event fromCreateEvent()and pass that struct to read/write operations that support overlapped I/O, then you can wait on the event. See Overlapped operations for more details. But, how you do all of that in Python, I have no clue.– Remy Lebeau
Nov 23 '18 at 10:36
Microsofts C implementation provides functions that can transform fd's into operating system handles (
_ofshandleiirc). Does Python not have a similar thing?– Chris Becke
Nov 23 '18 at 12:01