pthead_create causes error status 0x7F00 - c

Question

I'm trying to get a pthread example to run on my Windows 10 64-bit machine
I'm compiling using the most recent version of cygwin (64-bit), compiling the code as
gcc thread.c -pthread -o main.exe
which compiles with no error. thread.c looks like so:
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
void *worker_thread(void *arg)
{
printf("This is worker_thread()\n");
pthread_exit(NULL);
}
int main()
{
int a = fork();
if (a == 0) {
printf("child a=%d\n", a);
pthread_t my_thread;
int ret = pthread_create(&my_thread, NULL, &worker_thread, NULL);
printf("ret = %d\n", ret);
} else {
printf("parent a=%d\n", a);
int status;
wait(&status);
printf("status = 0x%X (%d)\n", status, status);
}
return 0;
}
On my machine, the output looks like so:
parent a=10868
child a=0
status = 0x7F00 (32512)
which is happening because pthread_create is causing my code to exit.
According to this, this error means:
"It didn't die from a signal, a core dump wasn't produced, and it exited with code 127 (0x7F).
What 127 means is unclear, which is why it should accompanied by an error message."
On my windows 8 64-bit machine, the code runs as expected, with the same build of cygwin (64-bit) installed, and returns this output.
parent a=26744
child a=0
ret = 0
this is worker_thread()
status 0x0 (0)
Any help would be much appreciated.