stdout

I need to run applications submitted by users. My code looks like: def run_app(app_path): inp = open("app.in", "r") otp = open("app.out", "w") return subprocess.call(app_path, stdout=otp, stdin=inp) Now since I have no control over what users will submit, I want to restrict the size of the output of the application. Other things like trying to access unauthorized system resources and abusing of CPU cycles are being restricted by apparmor rule enforcement. The maximum time allowed to run is being handled by parent process (in python). Now a rogue application can still try to flood the server

I knew the reason for this a while back but I have since forgotten and 5 mins of googling hasn't revealed the answer. I have written a python script which has two handlers. One for files and one for streams. Everything works as I want. Now, I wanted to quickly grep for something in the output that was being printed to the terminal but piping the script's output through grep doesn't appear to be working in that all of the output still get's printed to the terminal. I am using unix and python 2.7 This is probably a duplicate question but I can't find the answer. Here's my setup of the logging

I have an array of double pointers, but every time I try do print one of the values the address gets printed. How do I print the actual value? cout << arr[i] ? cout << &arr[i] ? they both print the address Does anyone know? If it's really an array of (initialized) double pointers, i.e.: double *arr[] = ... // Initialize individual values all you need is: cout << *arr[i]; cout << *(arr[i]) will print the value. cout << *(arr[i]); If "arr" is declared as double* arr[..]; Then you would use: cout << *(arr[i]) 来源： https://stackoverflow.com/questions/2485565/c-print-value-of-a-pointer

Because of stdin and stdout buffering sometimes printf , scanf and getchar are not executed. I usually flush output buffer using fflush(stdout) but code can become very unreadable because of that. If I set stdin and stdout unbuffered using setbuf(stdin, NULL) and setbuf(stdout, NULL) will I make my program perform better or worse? Making stdin or stdout completely unbuffered can make your program perform worse if it handles large quantities of input / output from and to files. Most I/O requests will be broken down as system calls on a byte by byte basis. Note that buffering does not cause

Eli Bendersky has explained thoroughly how to " Redirecting all kinds of stdout in Python ", and specifically Redirecting C-level streams, e.g. stdout of a shared library (dll). However, the example is in Linux and does not work in windows, mainly due to the following lines: libc = ctypes.CDLL(None) c_stdout = ctypes.c_void_p.in_dll(libc = ctypes.CDLL(None), 'stdout') How can we make it work in Windows? I found the answer buried in Drekin's code . Based on that, I made a small change to Eli Bendersky's example : Update: This code has been tested on Python 3.4 64-bit on Windows and Python 3.5

I am trying to read out data from a set of print statements in a C++ program that is being run using a subprocess. C++ code: printf "height= %.15f \\ntilt = %.15f \(%.15f\)\\ncen_volume= %.15f\\nr_volume= %.15f\\n", height, abs(sin(tilt*pi/180)*ring_OR), abs(tilt), c_vol, r_vol; e; //e acts like a print Python code: run = subprocess.call('Name', stdout = subprocess.PIPE, env={'LANG':'C++'}) data, error = run.communicate() However instead of getting the data, all I am getting is a single int, the exit code, either a 0 or an error code. Of course, python then tells me "AttributeError: 'int'

I don't understand why sometimes I need to use fflush() and sometimes not. My program is segfaulting at the moment and I am debugging it with print statements. When a program segfaults, does stdout not flush its buffer automatically? I don't understand why sometimes I need to use fflush() and sometimes not. Sometimes the stdio buffers are flushed sometimes they aren't. For example simply including a "\n" in the printed stuff will typically flush it (because stdout is by default line-buffered when attached to a terminal). When a program segfaults, does stdout not flush its buffer automatically

I am new to node.js and socket.io and I am trying to write a small server that will update a webpage based on python output. Eventually this will be used for a temperature sensor so for now I have a dummy script which prints temperature values every few seconds: Thermostat.py import random, time for x in range(10): print(str(random.randint(23,28))+" C") time.sleep(random.uniform(0.4,5)) Here's a cut down version of the server: Index.js var sys = require('sys'), spawn = require('child_process').spawn, thermostat = spawn('python', ["thermostat.py"]), app = require('express')(), http = require(