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Full Discussion: Unix Shell background processing
Top Forums Programming Unix Shell background processing Post 302457316 by Mercfh on Monday 27th of September 2010 06:09:09 PM
Old 09-27-2010
EDIT WOOT IT WORKS.
check dis out
Code:
#include <sys/wait.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
#include <string>
#include <iostream>
#include <stdlib.h> 

using namespace std;

bool ParseArg(char* cmnd, char* cmd[], char input[],bool BG)
{
		
        cout << "myshell> ";
        cin.getline(input,50);
	cmnd = strtok(input, " ");
	int i = 0;

	while(cmnd != NULL)
	{
	    
	    cmd[i] = cmnd;
	    if(strcmp(cmd[i], "&") == 0){
//Debug	    cout << "& found";
	    cmd[i] = NULL;
	    return true;
	}
	    
//Debug	    cout << cmd[i] << " ";
	    i++;
	    cmnd = strtok(NULL, " ");
	}
	return false;
}

void Clean(char* cmd[])
{
//Clean Array
        for(int a=0; a < 40; a++)
        {
             cmd[a] = NULL;
        }
}

void Execute(char* cmd[])
{
    pid_t pid;
    pid = fork();
    switch(pid)
    {
        case -1:  
            cout << "DEBUG:Fork Failure" << endl;
            exit(-1);
        case  0:
            execvp(cmd[0], cmd);
            
            if(execvp(cmd[0], cmd) == -1)
            {
                cout << "Command Not Found" << endl;
                exit(0);
            }
   
        default:  
            wait(NULL);
            cout << "DEBUG:Child Finished" << endl;
    }
    
}

int main()
{
   char* cmnd;
   char* cmd[40];
   char input[50]; 
   bool BG = false;

	

   while(cmd[0] != NULL)
   {
    	Clean(cmd);
   	BG = ParseArg(cmnd, cmd, input, BG);
	cout << BG;
   	if(strcmp(cmd[0], "exit") == 0 || strcmp(cmd[0], "quit") == 0 )
   	{
             break;
   	}
	else
	{
            Execute(cmd);
	}
	
   }

   return 1;

}

It returns a bool & when it finds one, then removes it. I checked with some debug statements but it works and removes the & correctly so it can do the statements normally.

Problem is now......getting background process to run.......which im derping on bigtime

here is a copy of the output, notice the 0 next to DEBUG, and the 1 when & is found. it means the Bool BG is turned on, when it finds an &.

I

myshell> ls -a
. .. a.out fork.c Hello .hi shell shell.c
0DEBUG:Child Finished
myshell> ls -l &
total 36
-rwxr-xr-x 1 matt matt 8435 2010-09-26 20:43 a.out
-rw-r--r-- 1 matt matt 943 2010-09-26 20:44 fork.c
drwxr-xr-x 2 matt matt 4096 2010-09-27 02:13 Hello
-rwxr-xr-x 1 matt matt 8292 2010-09-27 18:06 shell
-rw-r--r-- 1 matt matt 1570 2010-09-27 18:06 shell.c
1DEBUG:Child Finished
myshell>
Last edited by Mercfh; 09-28-2010 at 06:57 PM..
 

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LEARN ABOUT CENTOS

std::__atomic_base

std::__atomic_base< _IntTp >(3) 			     Library Functions Manual				   std::__atomic_base< _IntTp >(3)

NAME

       std::__atomic_base< _IntTp > -

SYNOPSIS

       Inherited by std::atomic< char >, std::atomic< char16_t >, std::atomic< char32_t >, std::atomic< int >, std::atomic< long >, std::atomic<
       long long >, std::atomic< short >, std::atomic< signed char >, std::atomic< unsigned char >, std::atomic< unsigned int >, std::atomic<
       unsigned long >, std::atomic< unsigned long long >, std::atomic< unsigned short >, and std::atomic< wchar_t >.

   Public Member Functions
       __atomic_base (const __atomic_base &)=delete
       constexpr __atomic_base (__int_type __i) noexcept
       bool compare_exchange_strong (__int_type &__i1, __int_type __i2, memory_order __m1, memory_order __m2) noexcept
       bool compare_exchange_strong (__int_type &__i1, __int_type __i2, memory_order __m1, memory_order __m2) volatilenoexcept
       bool compare_exchange_strong (__int_type &__i1, __int_type __i2, memory_order __m=memory_order_seq_cst) noexcept
       bool compare_exchange_strong (__int_type &__i1, __int_type __i2, memory_order __m=memory_order_seq_cst) volatilenoexcept
       bool compare_exchange_weak (__int_type &__i1, __int_type __i2, memory_order __m1, memory_order __m2) noexcept
       bool compare_exchange_weak (__int_type &__i1, __int_type __i2, memory_order __m1, memory_order __m2) volatilenoexcept
       bool compare_exchange_weak (__int_type &__i1, __int_type __i2, memory_order __m=memory_order_seq_cst) noexcept
       bool compare_exchange_weak (__int_type &__i1, __int_type __i2, memory_order __m=memory_order_seq_cst) volatilenoexcept
       __int_type exchange (__int_type __i, memory_order __m=memory_order_seq_cst) noexcept
       __int_type exchange (__int_type __i, memory_order __m=memory_order_seq_cst) volatilenoexcept
       __int_type fetch_add (__int_type __i, memory_order __m=memory_order_seq_cst) noexcept
       __int_type fetch_add (__int_type __i, memory_order __m=memory_order_seq_cst) volatilenoexcept
       __int_type fetch_and (__int_type __i, memory_order __m=memory_order_seq_cst) noexcept
       __int_type fetch_and (__int_type __i, memory_order __m=memory_order_seq_cst) volatilenoexcept
       __int_type fetch_or (__int_type __i, memory_order __m=memory_order_seq_cst) noexcept
       __int_type fetch_or (__int_type __i, memory_order __m=memory_order_seq_cst) volatilenoexcept
       __int_type fetch_sub (__int_type __i, memory_order __m=memory_order_seq_cst) noexcept
       __int_type fetch_sub (__int_type __i, memory_order __m=memory_order_seq_cst) volatilenoexcept
       __int_type fetch_xor (__int_type __i, memory_order __m=memory_order_seq_cst) noexcept
       __int_type fetch_xor (__int_type __i, memory_order __m=memory_order_seq_cst) volatilenoexcept
       bool is_lock_free () const noexcept
       bool is_lock_free () const volatilenoexcept
       __int_type load (memory_order __m=memory_order_seq_cst) const noexcept
       __int_type load (memory_order __m=memory_order_seq_cst) const volatilenoexcept
       operator __int_type () const noexcept
       operator __int_type () const volatilenoexcept
       __int_type operator&= (__int_type __i) noexcept
       __int_type operator&= (__int_type __i) volatilenoexcept
       __int_type operator++ (int) noexcept
       __int_type operator++ (int) volatilenoexcept
       __int_type operator++ () noexcept
       __int_type operator++ () volatilenoexcept
       __int_type operator+= (__int_type __i) noexcept
       __int_type operator+= (__int_type __i) volatilenoexcept
       __int_type operator-- (int) noexcept
       __int_type operator-- (int) volatilenoexcept
       __int_type operator-- () noexcept
       __int_type operator-- () volatilenoexcept
       __int_type operator-= (__int_type __i) noexcept
       __int_type operator-= (__int_type __i) volatilenoexcept
       __atomic_base & operator= (const __atomic_base &)=delete
       __atomic_base & operator= (const __atomic_base &) volatile=delete
       __int_type operator= (__int_type __i) noexcept
       __int_type operator= (__int_type __i) volatilenoexcept
       __int_type operator^= (__int_type __i) noexcept
       __int_type operator^= (__int_type __i) volatilenoexcept
       __int_type operator|= (__int_type __i) noexcept
       __int_type operator|= (__int_type __i) volatilenoexcept
       void store (__int_type __i, memory_order __m=memory_order_seq_cst) noexcept
       void store (__int_type __i, memory_order __m=memory_order_seq_cst) volatilenoexcept

Detailed Description
   template<typename _IntTp>struct std::__atomic_base< _IntTp >
       Base class for atomic integrals.

       Definition at line 117 of file atomic_base.h.

Author
       Generated automatically by Doxygen for libstdc++ from the source code.

libstdc++							  Tue Jun 10 2014				   std::__atomic_base< _IntTp >(3)
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