How to write to a named pipe

[Armin Gajda]

Hi,

I have to write to a named pipe that was created by another
(VisualBasic) program. It is running all under Windows XP.

I have read it should work with an ordinary file operation, so I tried:

1: File file = new File("\\\\.\\pipe\\SamplePipe");
2: FileWriter fw = new FileWriter(file);
3: fw.write ("Hi folk!");
4: fw.close ();

and also with an FileOutputStream. But as soon as the second line is
executed, the external program terminates and I get the message:

java.io.FileNotFoundException: \\.\pipe\SamplePipe (Alle Pipeinstanzen
sind ausgelastet)
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.<init>(FileOutputStream.java:176)
at java.io.FileOutputStream.<init>(FileOutputStream.java:131)
at java.io.FileWriter.<init>(FileWriter.java:73)

(The message's meaning in english: all pipe instances are busy)

So it knows that there is a pipe access, because if the external program
is not running it simply says 'file not found'.

If I use:

File file = new File("\\\\.\\pipe\\SamplePipe");
System.out.println("writable: " + file.canWrite ());

I get a true, and the external application terminates (what is actually
not wanted).

I use JDK 1.4.1_03.

Any hints?

 

[EJP]

1: File file = new File("\\\\.\\pipe\\SamplePipe");

Not sure about that dot: surely it should be a server name?

java.io.FileNotFoundException: \\.\pipe\SamplePipe (Alle Pipeinstanzen
sind ausgelastet)
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.<init>(FileOutputStream.java:176)
at java.io.FileOutputStream.<init>(FileOutputStream.java:131)
at java.io.FileWriter.<init>(FileWriter.java:73)

(The message's meaning in english: all pipe instances are busy)

This just indicates a problem at the named-pipe server end. It isn't
executing ConnectNmPipe() or whatever the API is called these days (12
years since I have looked at this). This is a Windows issue not a Java
issue. (You can't program the server end in Java.)