files in non-blocking mode?

[Uwe Mayer]

Hi,

I want two python programs to communicate over stdIO channels. The one
executes the other via the popen3 function:

amc = Popen3("./amc/amc.py", True, 0)
line = stdin.readline()
amc.tochild.write(line)
amc.tochild.flush()
print amc.fromchild.readlines()

The problem is that although amc.tochild gets flushed the data never reaches
the client until the .tochild fd is closed. Is there any way to put IO
channels into non-blocking mode in python?

Thanks
Uwe

[Mathias Waack]

Uwe Mayer wrote:

Hi,

I want two python programs to communicate over stdIO channels. The
one executes the other via the popen3 function:

amc = Popen3("./amc/amc.py", True, 0)
line = stdin.readline()
amc.tochild.write(line)
amc.tochild.flush()
print amc.fromchild.readlines()

The problem is that although amc.tochild gets flushed the data
never reaches the client until the .tochild fd is closed. Is there
any way to put IO channels into non-blocking mode in python?

How do you read the data in the client? Maybe you're using a line
buffered read? Does your code work if the server includes a trailing
CR and/or NL in the string before it calls the flush?

Mathias

[Uwe Mayer]

Sunday 28 November 2004 14:49 pm Mathias Waack wrote:

Uwe Mayer wrote:

I want two python programs to communicate over stdIO channels. The
one executes the other via the popen3 function:

amc = Popen3("./amc/amc.py", True, 0)
line = stdin.readline()
amc.tochild.write(line)
amc.tochild.flush()
print amc.fromchild.readlines()

The problem is that although amc.tochild gets flushed the data
never reaches the client until the .tochild fd is closed. Is there
any way to put IO channels into non-blocking mode in python?

How do you read the data in the client? Maybe you're using a line
buffered read? Does your code work if the server includes a trailing
CR and/or NL in the string before it calls the flush?

Yes, I used

line = stdin.readline()

and made sure the sending client had a newline ("\n") char appended to the
text. Still, the receiving client's readline() function does not return.

Uwe

[Jean Brouwers]

Try setting the unbuffered mode for the spawned process by using

"python -u ./amc/amc.py"
/Jean Brouwers
In article <co**********@news2.rz.uni-karlsruhe.de>, Uwe Mayer
<me*****@hadiko.de> wrote:

Sunday 28 November 2004 14:49 pm Mathias Waack wrote:

Uwe Mayer wrote:

I want two python programs to communicate over stdIO channels. The
one executes the other via the popen3 function:

amc = Popen3("./amc/amc.py", True, 0)
line = stdin.readline()
amc.tochild.write(line)
amc.tochild.flush()
print amc.fromchild.readlines()

The problem is that although amc.tochild gets flushed the data
never reaches the client until the .tochild fd is closed. Is there
any way to put IO channels into non-blocking mode in python?

How do you read the data in the client? Maybe you're using a line
buffered read? Does your code work if the server includes a trailing
CR and/or NL in the string before it calls the flush?

Yes, I used

line = stdin.readline()

and made sure the sending client had a newline ("\n") char appended to the
text. Still, the receiving client's readline() function does not return.

Uwe