CODEWITHSUNDEEP
c++winapi
Nghĩa Vũ Trung
Nghĩa Vũ Trung

Reputation: 5

Can't get next user command right after "consoleHandler" function get Ctrl-C from user

I writing a tiny shell for my subject and I need to catch Ctrl-C and handle it. I have a infinity loop to get user command until they type "exit". When I haven't type Ctrl-C everything is ok, my program get user command and handle it one by one. But when I type Ctrl-C, my program don't get any user command from that time. And I have an infinity loop but I can't type anything except for Ctrl-C.

I try to put a fflush(stdin) begore getline but it doesn't work. I try to list all threads in the process and it is always one. There is always one thread. 

#include<iostream>
#include<windows.h>
#include<stdio.h>
#include<stdio.h>
#include<tchar.h>
#include<psapi.h>
#include<vector>
#include<string>
using namespace std;

BOOL WINAPI consoleHandler(DWORD signal)
{
   if(signal == CTRL_C_EVENT)
      cout << "^C";
   return TRUE;
}

int main()
{
   SetConsoleCtrlHandler(consoleHandler, TRUE);
   string userInput;
   while(true)
      getline(cin, userInput);

return 0;
}

Expect: After I type CTRL-C console print "^C" and the program will get my next command

Upvotes: 0

Views: 58

Answers (1)

Max Vollmer
Max Vollmer

Reputation: 8598

Your input stream has an error bit set after Ctrl-C was sent. You need to clear it, otherwise std::getline will not read any characters from the stream and simply return:

BOOL WINAPI consoleHandler(DWORD signal)
{
    if (signal == CTRL_C_EVENT)
    {
        std::cout << "^C\n";
        std::cin.clear();
    }
    return TRUE;
}

Upvotes: 1

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