On Apr 7, 1:08 pm, akineko <akin...@gmail.com> wrote: > Hello everyone, > > I'm trying to use named pipes to fuse a Python program and a C > program. > One side creates pipes using os.mkfifo() and both sides use the same > named pipes (one side reads, another side writes). The read side uses > select.select() to wait for incoming messages and read the message > when select.select() says it is ready. > > The length of the message is unknown to the read side. > I cannot use file.read() because it will block waiting for an EOF. > I cannot use file.readline() because how many lines have arrived is > unknown. > So, I needed to use os.read() with the exact number of characters to > read. > > Under Solaris environment, os.fstat() provides the exact size of the > message that has arrived. > Thus, two processes can communicate each other through the named pipes > without blocking. > > However, the above scheme didn't work under Linux. > Linux os.fstat() returns size=0 even the message is pending. > (I think Linux buffers the message in memory while Solaris buffers the > message in a file system) > > My question is, how can I make the named pipe scheme work under Linux? > Is there any way to read the message without getting blocked? > > I know this is more Linux question than Python question but I believe > many Python programmers are strong Linux programmers. > > Any suggestions will be appreciated. > > Best regards, > Aki Niimura
The SIMPL open source project (http://www.icanprogram.com/simpl) provides an ultra lightweight toolkit useful for joining Python programs to C programs using a Send/Receive/Reply mechanism first pioneered by QNX. SIMPL uses a fifo synchronized shared memory scheme for the local message pass. Through the use of generic surrogate pairs SIMPL processes can be distributed across TCP/IP or RS232 (think radio modem) networks often times without any changes or recompiles. Through the use of another type of generic surrogate a Python module running on a nonLinux OS can communicate transparently with a module running on a Linux box. A SIMPL application consists of two or more SIMPL modules collaborating in this way. SIMPL modules can be written in any number of languages including Python, C, C++, Tcl/Tk or JAVA. More importantly SIMPL modules written in different languages can be mixed in a given SIMPL application. There is a Sudoku puzzle solver example here: http://www.icanprogram.com/simplBook/simplBook.self.html bob SIMPL project facilitator -- http://mail.python.org/mailman/listinfo/python-list
