multi-process file I/O problem

multi-process file I/O problem

Post by Paul Thiess » Tue, 15 Aug 1995 04:00:00

Hello. I've got an easy question, I hope, for you advanced unix hackers:

I've got a program that writes a file (an input to a raytracer) that eventually
calls the raytracer itself (via "system" or "exec"), which should read that
file.  Unfortunately, when the raytracer tries to "fopen" that file, it pukes.
I am assuming this has something to do with output file buffering or some such
  My question is simple: how do I close or flush or whatever the file I'm
creating such that it can be "fopen"ed from a called program/process? My
understanding is that an fclose(...) statement flushes the buffer, and I can
read the file from another window just fine, it's all there. The problem only
occurs when the file is "fopen"ed from a process called by the program creating
the file.
  Help! I'm on an Iris Indigo running IRIX 5.2, if that makes a difference.
I don't know if this is a platform-specific problem...
  Thanks for your help!

- Paul Thiessen


1. How can UNIX Multi-process with Multi-process interface

I am fairly new to UNIX so pardon me if the following questions seem trivial.
I have some basic UNIX books, but they do not cover the following:

I have two applications that can run totally independent.  My goal is to
link the two programs via stdout and file sharing.  Because each process
is computationally intensive, I would like to run the process concurrently
on two different processors (either one machine when dual processors are
available to me, or two machines).  I realize this is a global hunger
problem so my initial goal is to have both programs running on one machine

From my simple point of view, two possibilities come to mind:

        1.  Have each process run in the background of a single shell
        2.  Have each process run under seperate shells

I would appreciate any information on how to accomplish this task or where
I can get the information to accomplish this task.

Note:  I have an HP 715/50 and reading the man pages on the shell (ksh) has
only confused me.

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