I have started a C++ class in school, and my first assignment is, naturally, HelloWorld. My code is as follows:
#include "stdafx.h"
#include <iostream>
using namespace System;
int main(array<System::String ^> ^args)
{
Console::WriteLine("Hello World");//print hello world
system("PAUSE");//wait for button press
return 0;
}
It works as expected, except after I 'press any key to continue', the prompt comes up again. The last lines of output in Visual Studio look as follows:
The thread 'Win32 Thread' (0x1664) has exited with code 0 (0x0).
The thread 'Win32 Thread' (0x11f4) has exited with code 0 (0x0).
The program '[3032] HelloWorld.exe: Managed (v4.0.30319)' has exited with code 0 (0x0).
The program '[3032] HelloWorld.exe: Native' has exited with code 0 (0x0).
So, it appears it literally starts the application in 2 separate threads. Why would that happen? Thanks in advance.
Had the same problem today with a c# console application. Every time I executed the .exe file the window opened and after some time it would close and a new one popped up. After doing some research I found that I had to disable the Avast Antivirus 'Deep Screen' feature. It now runs properly.
i hade same problem.
i resolved my issue with
#include "stdafx.h"
#include <stdio.h>
#include <iostream>
using namespace std;
int _tmain(int argc, _TCHAR* argv[])
{
system("PAUSE");
return 0;
}
instead of ... return0; and after it, system("PAUSE");
Related
Our team uses Qt Creator. We have quite large projects, and for each project we have a test project with a test class for every production class. The main of the test project calls QTest::qExec for every test class. We run our tests by simply running the test project.
That works fine, but the output is limited to the console, looking like this:
********* Start testing of TestClass1 *********
Config: Using QtTest library 5.10.1, Qt 5.10.1 (x86_64-little_endian-lp64 shared (dynamic) debug build; by GCC 7.3.0)
PASS : TestClass1::initTestCase()
PASS : TestClass1::test1()
PASS : TestClass1::test2()
PASS : TestClass1::cleanupTestCase()
Totals: 2 passed, 0 failed, 0 skipped, 0 blacklisted, 3ms
********* Finished testing of TestClass1*********
********* Start testing of TestClass2 *********
Config: Using QtTest library 5.10.1, Qt 5.10.1 (x86_64-little_endian-lp64 shared (dynamic) debug build; by GCC 7.3.0)
PASS : TestClass2::initTestCase()
PASS : TestClass2::test1()
PASS : TestClass2::test2()
PASS : TestClass2::cleanupTestCase()
Totals: 2 passed, 0 failed, 0 skipped, 0 blacklisted, 3ms
********* Finished testing of TestClass2*********
I just discovered the integrated test gui and would really like to use it. However, I can't get the scanner (Tools->Tests->Rescan tests) to find all tests in a project. If I write this in the main it works fine for TestClass1:
int main(int argc, char** argv) {
TestClass1 test;
return QTest::qExec(&test, argc, argv);
}
However, if I try to add TestClass2 as below the scanner only recognizes TestClass2:
int main(int argc, char** argv) {
TestClass1 test1;
int ret = QTest::qExec(&test1, argc, argv);
TestClass2 test2;
int ret &= QTest::qExec(&test2, argc, argv);
return ret;
}
It seem as if the scanner only finds the last class executed with QTest::qExec.
Any idea how I could get it to find all tests, without touching the existing test classes?
This is my first time using QMap and I don't know what I'm doing wrong.
#include <QMap>
QMap<QString, int> name_sec_age;
name_sec_age.insert("willy", 593381460);
my errors are:
"unknown type name 'name_sec_age'"
and "expected unqualified id"
I'm using Qt Creator 4.0 with Qt 5.6 on a mac.
Side note: the run button on Qt Creator isn't available. To run my app I build it and then open the app from its path in finder. rather annoying.
You can't run code in the wild like that, it needs to be in a function.
#include <QMap>
#include <QString>
#include <QDebug>
int main() {
QMap<QString, int> name_sec_age;
name_sec_age.insert("willy", 593381460);
qDebug() << name_sec_age;
}
Your setup must be messed up somehow. Perhaps you'll have more luck by installing macports and using Qt/Qt Creator from there.
The following compiles just fine for me under Qt 5.5.1:
#include <QMap>
int main() {
QMap<QString, int> name_sec_age;
name_sec_age.insert("willy", 593381460);
}
When I try to run an application (just a simple hello_world.c doesn't work) I receive this error every time:
mpiexec -ckpointlib blcr -ckpoint-prefix /tmp/ -ckpoint-interval 10 -machinefile /tmp/machinefile -n 1 ./app_name
[proxy:0:0#masterpi] requesting checkpoint
[proxy:0:0#masterpi] checkpoint completed
[proxy:0:0#masterpi] requesting checkpoint
[proxy:0:0#masterpi] HYDT_ckpoint_checkpoint (./tools/ckpoint/ckpoint.c:111): Previous checkpoint has not completed.[proxy:0:0#masterpi] HYD_pmcd_pmip_control_cmd_cb (./pm/pmiserv/pmip_cb.c:905): checkpoint suspend failed
[proxy:0:0#masterpi] HYDT_dmxu_poll_wait_for_event (./tools/demux/demux_poll.c:77): callback returned error status
[proxy:0:0#masterpi] main (./pm/pmiserv/pmip.c:206): demux engine error waiting for event
[mpiexec#masterpi] control_cb (./pm/pmiserv/pmiserv_cb.c:202): assert (!closed) failed
[mpiexec#masterpi] HYDT_dmxu_poll_wait_for_event (./tools/demux/demux_poll.c:77): callback returned error status
[mpiexec#masterpi] HYD_pmci_wait_for_completion (./pm/pmiserv/pmiserv_pmci.c:197): error waiting for event
[mpiexec#masterpi] main (./ui/mpich/mpiexec.c:331): process manager error waiting for completion
I want just to make a checkpoint and nothing else (and restart later).
Thanks in advance
UPDATE:
I have tried with MPICH2, no chance. Or maybe I'm wrong somewhere...
pi#raspberrypi ~ $ mpiexec -n 1 -ckpointlib blcr -ckpoint-prefix /tmp/ -ckpoint-interval 2 ./test3
Count to: 0
[proxy:0:0#raspberrypi] requesting checkpoint
[proxy:0:0#raspberrypi] checkpoint completed
Count to: 1
[proxy:0:0#raspberrypi] requesting checkpoint
[proxy:0:0#raspberrypi] HYDT_ckpoint_checkpoint (/tmp/mpich/mpich2-1.5/src/pm/hydra/tools/ckpoint/ckpoint.c:111): Previous checkpoint has not completed.[proxy:0:0#raspberrypi] HYD_pmcd_pmip_control_cmd_cb (/tmp/mpich/mpich2-1.5/src/pm/hydra/pm/pmiserv/pmip_cb.c:902): checkpoint suspend failed
[proxy:0:0#raspberrypi] HYDT_dmxu_poll_wait_for_event (/tmp/mpich/mpich2-1.5/src/pm/hydra/tools/demux/demux_poll.c:77): callback returned error status
[proxy:0:0#raspberrypi] main (/tmp/mpich/mpich2-1.5/src/pm/hydra/pm/pmiserv/pmip.c:210): demux engine error waiting for event
[mpiexec#raspberrypi] control_cb (/tmp/mpich/mpich2-1.5/src/pm/hydra/pm/pmiserv/pmiserv_cb.c:201): assert (!closed) failed
[mpiexec#raspberrypi] HYDT_dmxu_poll_wait_for_event (/tmp/mpich/mpich2-1.5/src/pm/hydra/tools/demux/demux_poll.c:77): callback returned error status
[mpiexec#raspberrypi] HYD_pmci_wait_for_completion (/tmp/mpich/mpich2-1.5/src/pm/hydra/pm/pmiserv/pmiserv_pmci.c:196): error waiting for event
[mpiexec#raspberrypi] main (/tmp/mpich/mpich2-1.5/src/pm/hydra/ui/mpich/mpiexec.c:325): process manager error waiting for completion
Test3-Code:
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <mpi.h>
int main(int argc, char* argv[]) {
int rank;
int size;
int i = 0;
MPI_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
MPI_Comm_size(MPI_COMM_WORLD, &size);
MPI_Status status;
if (rank == 0) {
for(i; i <=100; i++){
int j = 0;
while(j < 100000000){
j++;
}
printf("Count to: %i\n", i);
}
} else {
}
MPI_Finalize();
return 0;
}
I just need to have one successful checkpoint and to show the restart.
If someone has a working example (irrelevant what it makes, simple working "Hello World" would make me happy!) I would be very glad.
Happy new year!
Unfortunately, the checkpoint/restart code in MPICH 3.0.4 is known to be buggy at the moment. That will hopefully get fixed in a future release. It looks like you're probably using it correctly. It's possible that if you go back to a previous version, you might have better luck.
Here the problem was with the too small interval for checkpointing.
Setting it to 20s or more has solved this (but not the other :( ) problem.
I am trying to create a GUI in Qt4 for my tcl based tool. In order to populate widgets I need to execute some tcl commands. I read about QProcess and I am invoking tcl scripts using QProcess and then grabbing their output from stdout.
Suppose I execute 3 commands in tcl then when I query stdout I believe I should see 3 outputs corresponding to each of the three commands, however this is not happening consistently. Behavior is flaky.
As you can see in the main.cpp I am executing multiple commands using runTclCommand() function and in the end executing getData() function to read stdout.
main.cpp:
#include <QApplication>
#include <QProcess>
#include <QDebug>
#include "Tclsh.h"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QByteArray out;
Tclsh *tcl = new Tclsh;
tcl->startTclsh();
tcl->runTclCommand("set ::tcl_interactive 1\n");
tcl->runTclCommand("set a 23\n");
tcl->runTclCommand("puts $a\n");
tcl->runTclCommand("set a 40\n");
tcl->runTclCommand("puts $a\n");
// out = idl->getData();
out = tcl->getData();
}
Tclsh.cpp:
#include <QProcessEnvironment>
#include <QProcess>
#include <QDebug>
#include "Tclsh.h"
void Tclsh::startTclsh() {
QString program = "/usr/bin/tclsh8.4";
this->setProcessChannelMode(QProcess::MergedChannels);
this->start(program);
if ( !this->waitForStarted()) {
qDebug()<<"ERROR Starting tclsh";
}
return;
}
void Tclsh::runTclCommand(const char *cmd) {
qDebug()<<"CMD:"<<cmd;
this->write(cmd);
if (!this->waitForBytesWritten()) {
qDebug()<<"Error in writing data";
}
}
QByteArray Tclsh::getData() {
if (!this->waitForReadyRead()) {
qDebug()<<"Error in reading stdout: Ready read signal is not emitted";
}
QByteArray data = this->readAllStandardOutput();
qDebug()<<"DATA:"<<data;
return data;
}
However, sometime I get the following output:
CMD: set ::tcl_interactive 1
CMD: set a 23
CMD: puts $a
CMD: set a 40
CMD: puts $a
DATA: "1
% 23
% 23
% "
And sometimes this:
CMD: set ::tcl_interactive 1
CMD: set a 23
CMD: puts $a
CMD: set a 40
CMD: puts $a
DATA: "1
"
I do not understand why this is happening. I would really appreciate if someone can point me to the error in my approach here.
Thanks,
Newbie
Edit: After some more research, here are my thoughts
According to Qt manual, readyRead signal will be emitted whenever new data is available (as specified by #Frank Osterfeld also, thanks!). It will not wait for complete output data to be available (which is justified since it does not know when will that happen). Hence my approach is not good. What I can do is something like this:
start the process -> wait for process to finish -> read stdout
This will ensure that flaky behavior does not arise as process is already finished when I am reading hence no new data can come.
However, in this proposed approach I am not clear about one thing: Does stdout is specific to a process? I mean can it happen that process which was supposed to read stdout output from process1, can get other stdout data from some other process which happen to write stdout at the same time as process1?
Thanks,
Newbie
I am closing this question. Reading from a channel more than once does not seem to a be a good idea. Instead what I do now is write what I want to write in one go --> close the channel for writing --> then read it back. In that way I get consistent output.
kill -s SIGCHLD
The above is the code for killing any zombie process, But my question is:
Is there any way by which a Zombie process manifest itself??
steenhulthin is correct, but until it's moved someone may as well answer it here. A zombie process exists between the time that a child process terminates and the time that the parent calls one of the wait() functions to get its exit status.
A simple example:
/* Simple example that creates a zombie process. */
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
int main(void)
{
pid_t cpid;
char s[4];
int status;
cpid = fork();
if (cpid == -1) {
puts("Whoops, no child process, bye.");
return 1;
}
if (cpid == 0) {
puts("Child process says 'goodbye cruel world.'");
return 0;
}
puts("Parent process now cruelly lets its child exist as\n"
"a zombie until the user presses enter.\n"
"Run 'ps aux | grep mkzombie' in another window to\n"
"see the zombie.");
fgets(s, sizeof(s), stdin);
wait(&status);
return 0;
}