Parent process exits twice using fork() execv() in c++ - c++

Question

I have a multiprocessing application that works well, except the parent process seems to exit twice.
I left out some of the code for simplification. Basically, I use libcurl (I wrote my own abstraction layer for it) to get JSON data from a server (left the code for this out) and then the simdjson library to iterate through it and run worker processes where required.
At the end I wait for all child processes (in the parent process) to terminate before printing "done". I can see however, that my program is printing "done" twice. I presume once after it's done in the for loop to create all the worker processes and then again once the last child returns. At least that is what I can see from the output on the console, as the child processes print to the console as well. However, given that I use if (pid_fork > 0), i.e. I must be in the parent process, any subsequent code should be executed only once. What am I doing wrong?
#include <iostream>
#include <vector>
#include <unistd.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "simdjson.h"
int main (int argc, char *argv[])
{
/* some other code */
pid_t pid_fork;
std::vector<int> v_pid;
// loop through json
for (simdjson::dom::element mq_item : json_mq_items)
{
pid_fork = fork();
if (pid_fork == -1)
{
std::cout << "error: could not fork process" << std::endl;
return EXIT_FAILURE;
} else if (pid_fork > 1) // parent process
{
v_pid.push_back(pid_fork);
}
else // child process (pid_fork == 0)
{
char *argv[] = { (char*)(std::string("foo")), NULL };
if (execv((static_cast<std::string>("./foo")).c_str(), argv) == -1)
{
std::cout << "could not load child" << std::endl;
return EXIT_FAILURE;
}
}
}
// in parent process only
if (pid_fork > 0)
{
// Wait for all child processes to terminate
for (size_t i = 0; i < v_pid.size(); i++)
{
while (waitpid(v_pid[i], NULL, 0) > 0);
}
/* some other code */
std::cout << "done" << std::endl;
return EXIT_SUCCESS;
}
}