Source code for triqs.utility.redirect

# Copyright (c) 2013 Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
# Copyright (c) 2013 Centre national de la recherche scientifique (CNRS)
# Copyright (c) 2020 Simons Foundation
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# GNU General Public License for more details.
# You may obtain a copy of the License at
# Authors: Olivier Parcollet, Nils Wentzell

import threading, time, sys, os, fcntl

__all__ = ['start_redirect', 'stop_redirect']

# A thread that will redirect the c++ stdout to the ipython notebook
[docs] class T(threading.Thread):
[docs] def __init__(self): threading.Thread.__init__(self) self.go_on = True # copy the c++ stdout handler for later self.oldhandle = os.dup(1)
[docs] def stop(self): self.go_on = False
[docs] def run(self): # create a pipe and glue the c++ stdout to its write end # make the read end non-blocking piper, pipew = os.pipe() os.dup2(pipew, 1) os.close(pipew) fcntl.fcntl(piper,fcntl.F_SETFL,os.O_NONBLOCK) while self.go_on: # give the system 1 second to fill up the pipe time.sleep(1) try: # read out the pipe and write it to the screen # if the pipe was empty it return an error (hence the try-except) sys.stdout.write(, 10000)) sys.stdout.flush() except: pass # when we want to stop the thread put back the c++ stdout where it was # clear the pipe os.dup2(self.oldhandle, 1) os.close(piper) return
# flag to know if the thread was started started = False # start the redirection
[docs] def start_redirect(): global started global a if started: print("Already redirected c++ output") else: started = True # start a new redirection thread a = T() a.start()
# stop the redirection
[docs] def stop_redirect(): global started global a if started: started = False a.stop()