finish the research for python-subprocess

@@ -3,15 +3,18 @@
 
 
 import sys, shlex, time, subprocess
 import sys, shlex, time, subprocess
 
 
-cmd = "./python.subprocess 0 800"
+cmd = "./python.subprocess 0 80000"
 args = shlex.split(str(cmd))
 args = shlex.split(str(cmd))
 print "cmd: %s, args: %s"%(cmd, args)
 print "cmd: %s, args: %s"%(cmd, args)
 
 
+# the communicate will read all data and wait for sub process to quit.
 def use_communicate(args, fout, ferr):
 def use_communicate(args, fout, ferr):
     process = subprocess.Popen(args, stdout=fout, stderr=ferr)
     process = subprocess.Popen(args, stdout=fout, stderr=ferr)
     (stdout_str, stderr_str) = process.communicate()
     (stdout_str, stderr_str) = process.communicate()
     return (stdout_str, stderr_str)
     return (stdout_str, stderr_str)
 
 
+# if use subprocess.PIPE, the pipe will full about 50KB data,
+# and sub process will blocked, then timeout will kill it.
 def use_poll(args, fout, ferr, timeout):
 def use_poll(args, fout, ferr, timeout):
     (stdout_str, stderr_str) = (None, None)
     (stdout_str, stderr_str) = (None, None)
     process = subprocess.Popen(args, stdout=fout, stderr=ferr)
     process = subprocess.Popen(args, stdout=fout, stderr=ferr)
@@ -28,19 +31,14 @@ def use_poll(args, fout, ferr, timeout):
         time.sleep(1)
         time.sleep(1)
     process.wait()
     process.wait()
     return (stdout_str, stderr_str)
     return (stdout_str, stderr_str)
-def use_communicate_timeout(args, fout, ferr, timeout):
-    (stdout_str, stderr_str) = (None, None)
-    process = subprocess.Popen(args, stdout=fout, stderr=ferr)
-    starttime = time.time()
-    while True:
 
 
+# stdout/stderr can be fd, fileobject, subprocess.PIPE, None
 fnull = open("/dev/null", "rw")
 fnull = open("/dev/null", "rw")
-fout = subprocess.PIPE#fnull.fileno()
-ferr = subprocess.PIPE#fnull#fnull.fileno()
+fout = fnull.fileno()#subprocess.PIPE#fnull#fnull.fileno()
+ferr = fnull.fileno()#subprocess.PIPE#fnull#fnull.fileno()
 print "fout=%s, ferr=%s"%(fout, ferr)
 print "fout=%s, ferr=%s"%(fout, ferr)
 #(stdout_str, stderr_str) = use_communicate(args, fout, ferr)
 #(stdout_str, stderr_str) = use_communicate(args, fout, ferr)
-#(stdout_str, stderr_str) = use_poll(args, fout, ferr, 10)
-(stdout_str, stderr_str) = use_communicate_timeout(args, fout, ferr, 10)
+(stdout_str, stderr_str) = use_poll(args, fout, ferr, 10)
 
 
 def print_result(stdout_str, stderr_str):
 def print_result(stdout_str, stderr_str):
     if stdout_str is None:
     if stdout_str is None: