Detached threads don't run simultaneously - c

Question

Hey so I'm trying to create a multithreaded program. The first thread takes in input from std in and stores it in a minheap. The second thread... well for now, all it does is print "sequencer thread works" and nothing else because it doesn't run properly.
Both threads are detached, so they should run simultaneously, and yet for some reason the second thread doesn't run until the first exits. Is it something simple I am overlooking? I'm new to multithreading.
Thanks
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <sys/time.h>
#include "MinHeap.h"
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
void* readerthread(MinHeap minheap, char eventlist[], char timestamp[])
{
char buffer[100];
char input;
int ret, len, fd;
while(1)
{
char *choice;
choice = malloc(50*sizeof(char));
fgets(choice, 50, stdin);
printf("choice = : %s", choice);
if(checkTimestamp(choice)==0)
{
pthread_mutex_lock(&mutex);
addElement(&minheap, choice);
pthread_mutex_unlock(&mutex);
}
free(choice);
printf( "min of minheap: %s\n", getMin(&minheap));
}
void* sequencerthread()
{
printf("sequencer works\n");
fflush(stdout);
pthread_exit(0);
}
int main(int argc, char *argv[])
{
if (argv < 2)
{
printf("not enough arguments. exiting...\n");
return 1;
}
char timestamp[50];
char event[50];
char eventlist[sizeof(char)+170];
int i;
char nowtimestamp[] = "2400/001/00/00/00";
MinHeap minheap;
initializeMinHeap(&minheap, intCompare, sizeof(char)*50);
strcpy(timestamp, argv[1]);
strcpy(event, argv[2]);
pthread_t ignore1, ignore2;
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
pthread_create(&ignore1, &attr, readerthread(minheap, eventlist, nowtimestamp), 0);
pthread_create(&ignore2, &attr, sequencerthread, 0);
pthread_attr_destroy(&attr);
pthread_exit(0);
return (EXIT_SUCCESS);
}

Answer 1

This line is the problem:
pthread_create(&ignore1, &attr, readerthread(minheap, eventlist, nowtimestamp), 0);
You're calling readerthread on the main thread and passing its result to pthread_create. Since readerthread never returns, you never even get to the first call to pthread_create, let alone the second one.
You need to call it like this instead:
pthread_create(&ignore1, &attr, readerthread, &readerthread_args);
where readerthread_args is a struct encapsulating the arguments to pass to readerthread. You'll also need to change readerthread to take a single void * argument, cast it to the type of readerthread_args, and unpack the args.
You should have got a whole bunch of warnings from your compiler. Did you remember to turn them on?