C++ not accessing method in ifstatement

Question

The if statement block now executes when I add the \n here:

printf("Executing the command: %s\n", cmd);

Before this addition, it didn't hit the getListofProcesses() method. The original code is shown below:

#include <stdio.h>
#include <unistd.h>
#include <cstring>
#include <stdlib.h>
#include <iostream>
#include <sys/wait.h>

char* getlistOfProcesses(const char* cmd) 
{
    FILE* pipe = popen(cmd, "r");
    if (!pipe) return (char*)"ERROR";
    char buffer[128];
    char *result = new char[1024];
    while(!feof(pipe)) {
        if(fgets(buffer, 128, pipe) != NULL)
            strcat(result, buffer);
    }
    pclose(pipe);
    return result;
}

int main(int argc, char **argv)
{   
    int P2C[2];
    int C2P[2];
    pipe(P2C);
    pipe(C2P);
    pid_t cPid = fork();
    char cmd[50];
    char* listOfProcesses = new char[1024];

    if (cPid == 0)
    {
        close(P2C[1]); 
        close(C2P[0]); 
        read(P2C[0], cmd, 50);
        if(strcmp(cmd,"LISTALL") == 0)
        {
            printf("Executing the command: %s", cmd);
            write(C2P[1], getlistOfProcesses("ps -ax -o pid,cmd"), 1024);
            close(P2C[0]);
            close(C2P[1]);
        }
    }
    else if (cPid > 0)
    {
        close(C2P[1]); 
        close(P2C[0]); 
        write(P2C[1], "LISTALL", 50);
        wait(NULL);
        read(C2P[0], listOfProcesses,1024);
        printf("%s\n",listOfProcesses); 
        close(C2P[0]);
        close(P2C[1]);
    }
    ...
    return 0;
}

I'm not sure if this is due to the way my pipes are done or if it is being accessed and I don't notice, I tried to check with a printf near the top of the method.

Answer 1

You need to include a newline in your format string, or call fflush(stdout)after your printf statement. See Why does printf not flush after the call unless a newline is in the format string? for more information.