Thanks for the suggestion, Michael. Reading it led to a bit of a forehead
slap.
Unfortunately, that didn't work either. Curiously, it appears that
the "show()" command does not return.
----- CODE SECTION -------------
#!/usr/local/bin/python
import os,sys
import pylab
def main():
x = pylab.linspace(-10,10,100)
y = pylab.sin(x)
pylab.plot(x,y)
sys.stderr.write("Begun.")
pylab.show()
sys.stderr.write("Done.")
if __name__ == "__main__":
main()
---- END CODE -------------
When executed from the command line:
$ ./test.py &
. . . the plot displays; clicking on the X closes it, but the process keeps
on running.
When executed as an argument to python:
$ python test.py &
. . . the same behavior (except it's a python process which hangs).
The two sys.stderr.write() statements are for debugging. The first one
executes; the second does not. My conclusion is that the show() command does
not return.
----------
When I operate interactively,
the command "pylab.plot(x,y)" opens a widow labeled "Figure 1".
. . . then . . .
the command "show()" writes the plot to that window (i.e., sine plot).
Clicking the X in the figure window causes the window to disappear, but
the "show()" command fails to return.
--------------
So . . . I figure that the lack of show() returning is the root problem.
Any suggestions?
I'm running Fedora 8, python 2.5.1, and matplotlib 0.91.2-1.fc8 from the yum
repository. Backend is set to GTKAgg in my matplotlibrc file.
James
-------
On Monday 07 July 2008 17:29:16 you wrote:
> Why do you want to "fork" the process? If you just run it in the
> background it should have the desired effect:
>
> <begin tst.py>
> from pylab import *
> x = linspace(-10,10,100) # or load data from a file.
> y = sin(x)
> plot(x,y)
> show()
> <end tst.py>
>
> $ python tst.py&
>
> Process remains in background running until the user closes the plot
> window, at which point it terminates.
>
> Michael.
>
> On 7 Jul 2008, at 2:30 PM, James K. Gruetzner wrote:
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > I'm not sure if this is the right venue for this question. I've
> > searched the
> > archives, but without success so far. If this is covered there (or
> > elsewhere
> > on the web), I'd apprciate a pointer to it so it doesn't duplicate
> > bandwidth
> > here.
> >
> > Anyway, what I'd like to do is have a python script which reads
> > data from a
> > file, displays an image/plot/whatever made from the data, and then
> > exits,
> > keeping the image displayed.
> >
> > I'm running Fedora 8, python 2.5.1, and matplotlib 0.91.2-1.fc8
> > from the yum
> > repository. Backend is set to GTKAgg in my matplotlibrc file.
> >
> > My initial attempt used the "double fork" method from the python
> > cookbook:
> >
> > - -------------Code follows----------------------
> > if __name__ == "__main__":
> >
> > #From Python Cookbook
> > try:
> > pid = os.fork()
> > if pid > 0:
> > # Exit first parent
> > sys.exit(0)
> > except OSError, e:
> > print >>sys.stderr, "fork #1 failed: %d (%s)" %(e.errno,
> > e.strerror)
> > sys.exit(1)
> >
> > # Decouple from parent environment
> > #os.chdir("/")
> > os.setsid()
> > os.umask(0)
> >
> > # Do second fork
> > try:
> > pid = os.fork()
> > if pid > 0:
> > # Exit from second parent; print eventual PID before exiting
> > print "Image PID %d" % pid
> > sys.exit(0)
> > except OSError, e:
> > print >>sys.stderr, "fork #2 failed: %d (%s)"%(e.errno,
> > e.strerror)
> > sys.exit(1)
> >
> > # Start the main loop to display image
> > main()
> >
> > - --------------END CODE--------------------------------------
> >
> > The main() function reads the values appropriately into the
> > variable "myarr",
> > and then calls imshow and show:
> >
> > - ------------ Code follows -------------------
> >
> >
> > pylab.imshow(myarr)
> > pylab.show()
> > - --------------END CODE--------------------------------------
> >
> > . . . and then exits.
> >
> > All works well until I try to kill the figure/image by clicking on
> > the X in
> > the upper-right corner. It disappears alright, but the process
> > remains
> > running, and I have to manually kill it with the kill -SIGTERM
> > <pid> command.
> >
> > I'd like the process to die when I close the window.
> >
> > I'm really an application programmer, not a system programmer, and
> > usually
> > don't delve this deeply into process management, so I'm probably doing
> > something extremely ignorant. Help is appreciated.
> >
> > Thanks!
> >
> > James
> >
> >
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