how can a variable entered in one thread be used in another thread ??

There is a thread1 where I enter an alphabet,
then in thread2 there I have to convert the character to its uppercase/lowercase and print that using a thread3... ??!!

Here is a rough code that I tried :

#include <stdio.h>
#include <pthread.h>
#include <stdlib.h>
#include <ctype.h>

void *input() {
   char chr;
   printf("Enter a character: ");
   scanf("%c", &chr);
}

void *upper_case(void *c) {
   char a;
   a = (char) c;

   if(isupper(a))  printf("\n%c", tolower(a));
   else if(islower(a))  printf("\n%c", toupper(a));
   else printf("\nOMG !");
}

void *print(void *c) {
   char str;
   str = (char) c;

   printf("%c", c);
}

int main(void) {
   pthread_t p1, p2, p3;
   
   pthread_create(&p1, NULL, input, NULL);
   pthread_create(&p2, NULL, upper_case, (void*));
   pthread_create(&p2, NULL, print, (void*));
.
.
.
. 
         I don't know what to do now ?? :(

Please help !!!

Have a look at following:-
a) Shared variable
b) Pipes
c) Signal

Even an small google search will help you.

[Quote]

Make the letter that you want to read as global variable..
Take a semaphore, and sychronise ur 3 threads using this semaphore busing using sem_wait and sem_post appropriately...