OpenMP not showing correct thread number - C - c

Question

I have a simple program that uses openMP to run 4 threads that read in 4 different text files and find anagrams. I am just trying to figure out why the last thread that is reported shows a thread number of 26478...I can't quite figure it out. The function countAnagrams doesn't do anything with tid, it just prints it to the screen when the function is done running.
Below is my code and the output. Any help would be greatly appreciated.
#include <omp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void countAnagrams(char* fileName, int threadNum);
void main ()
{
char *fileNames[] = {"AnagramA.txt","AnagramB.txt","AnagramC.txt","AnagramD.txt"};
int i;
int tid;
int nthreads = 4;
omp_set_num_threads(nthreads);
#pragma omp parallel
{
#pragma omp sections
{
#pragma omp section
{tid = omp_get_thread_num();
countAnagrams(fileNames[0], tid);}
#pragma omp section
{tid = omp_get_thread_num();
countAnagrams(fileNames[1], tid);}
#pragma omp section
{tid = omp_get_thread_num();
countAnagrams(fileNames[2], tid);}
#pragma omp section
{tid = omp_get_thread_num();
countAnagrams(fileNames[3], tid);}
}
}
}
Output:
Filename: AnagramD.txt
Hello from thread: 1
Number of anagrams: 286
Longest anagram: 8
Filename: AnagramB.txt
Hello from thread: 0
Number of anagrams: 1148
Longest anagram: 8
Filename: AnagramC.txt
Hello from thread: 2
Number of anagrams: 5002
Longest anagram: 8
Filename: AnagramA.txt
Hello from thread: 26478
Number of anagrams: 3184
Longest anagram: 8

Answer 1

What's causing your issue is that you have not declared your thread ID variable private when you create your parallel region. Thus, threads are stomping over each other there and garbage can result. To fix this, make sure that all variables that should only be accessible by a single thread are declared private like so:
#pragma omp parallel private(tid)

Answer 2

The thing that may cause this problem is that tid is declared in main function. Try to do it in the following manner:``
#include <omp.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void countAnagrams(char* fileName, int threadNum);
void main ()
{
char *fileNames[] = {"AnagramA.txt","AnagramB.txt","AnagramC.txt","AnagramD.txt"};
int i;
int nthreads = 4;
omp_set_num_threads(nthreads);
#pragma omp parallel private(tid) //now each thread has its private copy of tid
{
#pragma omp sections
{
#pragma omp section
{tid = omp_get_thread_num();
countAnagrams(fileNames[0], tid);}
#pragma omp section
{tid = omp_get_thread_num();
countAnagrams(fileNames[1], tid);}
#pragma omp section
{tid = omp_get_thread_num();
countAnagrams(fileNames[2], tid);}
#pragma omp section
{tid = omp_get_thread_num();
countAnagrams(fileNames[3], tid);}
}
}
}