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    <p>Some problems here:</p> <pre><code>if (argc != 2) </code></pre> <p>This means you're expecting the integer values to be quoted, i.e. <code>a.out "1 2 3 4 5"</code>. If you do things this way the numbers are represented as a single string, i.e. <code>argv[1] := "1 2 3 4 5"</code>.</p> <p>It's easier to check for <code>argc &lt; 2</code> and taking the arguments as <code>a.out 1 2 3 4 5</code>. This way each argument gets its own string, i.e. <code>argv[1] := "1", argv[2] := "2"</code> etc.</p> <p>You can of course use a quoted list instead, but then you have add some logic to extract the integers from the string (e.g. with <code>strtok</code>) whereas argument handling can do it for you instead.</p> <p>Second, your program expects at least six integers here, and also skips the first one (you want <code>i</code> to go from <code>0</code>:</p> <pre><code>for (i = 1; i &lt;= 5; i++) sum = sum + atoi(param[i]); </code></pre> <p>As for the upper limit, one way to convey the number of integers together with their strings is to use a struct:</p> <pre><code>struct arg_struct { int argc; char **argv; }; </code></pre> <p>and then use such a struct when calling <code>pthread_create</code>, i.e.</p> <pre><code>struct arg_struct args = { argc-1, argv+1 }; pthread_create(&amp;tid,&amp;attr,(void(*)(void *))(runner),(void *)(&amp;args)); </code></pre> <p>and change <code>runner</code> accordingly:</p> <pre><code>void *runner(struct arg_struct *param) { int i; sum = 0; for (i = 0; i &lt; param-&gt;argc; i++) sum = sum + atoi(param-&gt;argv[i]); pthread_exit(0); } </code></pre> <p>Here's the code with all changes:</p> <pre><code>#include &lt;pthread.h&gt; #include &lt;stdio.h&gt; struct arg_struct { int argc; char **argv; }; int sum; /* this data is shared by the thread(s) */ void *runner(struct arg_struct *); /* threads call this function */ int main(int argc, char *argv[]) { pthread_t tid; /* the thread identifier */ pthread_t tid2; pthread_attr_t attr; /* set of thread attributes */ struct arg_struct args = { argc-1, argv+1 }; if (argc &lt; 2) { fprintf(stderr,"usage: a.out &lt;integer values&gt;\n"); return -1; } pthread_attr_init(&amp;attr); pthread_create(&amp;tid,&amp;attr,(void *(*)(void *))(runner),(void *)(&amp;args)); pthread_join(tid,NULL); printf("sum = %d\n",sum); } /* The thread will begin control in this function */ void *runner(struct arg_struct *param) { int i; sum = 0; for (i = 0; i &lt; param-&gt;argc; i++) sum = sum + atoi(param-&gt;argv[i]); pthread_exit(0); } </code></pre>
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    1. POHow to store a list of inputs for multi-thread programming
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    1. POHow to store a list of inputs for multi-thread programming
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    1. COFirst of all, thank you very much for the help and explanation. May I ask one more question? How do I access the list of numbers that user entered? Because I want to do something more with the this list of numbers. I want to create another thread to find the min number of this list. I have the algothrim to find the min, `int smallest = INT_MAX; for (i = 0; i < param->argc; i++) { if(atoi(param->argv[i])<smallest){ sum=atoi(param->argv[i]); }` But as you can see I am trying to go through the list and compare each number entered and see if it's the smallest.
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