72 lines
1.9 KiB
C
72 lines
1.9 KiB
C
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/*
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Written By: Prawar Poudel
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13 Feb 2018
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This is written to demonstrate the usage of Thread Local Storage using key
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*/
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#include <pthread.h>
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#include <stdio.h>
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#include <unistd.h>
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#define NUM_THREADS 5
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#define ARRSIZE 5
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//in this program we will use a key defined by pthread_key_t to define a key
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pthread_key_t myKey;
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void printMyVal(int myId)
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{
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printf("Getting specific value for thread %d using key\n",myId); int *myVal = pthread_getspecific(myKey);
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printf("\t..The thread local value in thread id %d is %d\n",myId,*myVal);
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}
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//the argument that will be sent will be the (int) id
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void *simpleThreadFunc(void* argument)
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{
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int myId = (int)argument;
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//this variable will be thread specific value that we will print from other function
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int myVal = myId*100;
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printf("Creating the variable ::%d that will be referred to by Key from threadid %d\n",myVal,myId);
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if(!pthread_setspecific(myKey,(void*)&myVal))
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{}
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else
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{
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printf("Error in setting specific key in thread id %d\n",myId);
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}
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printMyVal(myId);
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}
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int main()
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{
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//you can create these dynamically also
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pthread_t myThreads[NUM_THREADS];
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int status = 0;
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pthread_key_create(&myKey,NULL);
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int i;
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for( i=0;i<NUM_THREADS;i++)
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{
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printf("Creating thread no. %d, and sending ID %d\n",i,i);
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status = pthread_create(&myThreads[i],NULL,simpleThreadFunc,(void*)i);
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if(status)
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{
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printf("Error in creating the threads: %d\n",i);
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return -1;
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}else
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{
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printf("Successful creation of thread %d..\n",i);
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}
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}
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//this is the area that threads will run
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//we will wait for the threads here
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for( i=0;i<NUM_THREADS;i++)
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{
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int retStatus = pthread_join(myThreads[i],NULL);
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if(!retStatus)
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{
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printf("Successful termination of thread id %d\n",i);
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}
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else
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printf("Well..... some problem at thread id %d, error no: %d\n",i,retStatus);
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}
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return 0;
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}
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