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copied!<p>Without providing some extra code to store the parameter <em>'during'</em> the <em>'last'</em> call to your function there is no chance at all to detect if it was called with the same value or another.</p> <p>As the <em>'current'</em> value of x will be living on the stack only it will be completely lost once your function call finishes. </p> <p>In the <strong>pre-multi-threading</strong> era just using a static variable to cache the value of x during the last run of your function <code>func</code> could (almost) have solved your problem:</p> <pre><code>void fun (int x) { static int old_value = VALUE_INVALID; if(x != old_value) printf("VALUE OF X IS DIFFERENT THAN PREVIOUS CALL \n"); old_value = x; } </code></pre> <p>The only problem still staying with this approach is re-entrancy - meaning the cached value might get screwed up if <code>func</code> gets called in a signal handler.</p> <p>If running in a <strong>multi-threaded</strong> application you additionally have to provide some kind of locking mechanism when using this approach or you'll get pretty much screwed up sooner or later.</p> <p>Probably you'll be screwed up in this scenario anyways as you would have to clarify what <em>'last'</em> call to function and value <em>'during'</em> execution exactly mean.</p> <p>Is the current right value that of thread A that entered func before thread B but is still executing or that of thread B that entered after B but which has finished execution of func already? </p>

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