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POFunction pointer and default argument
 

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    <p>Let's assume, I have a function with a prototype like (in <code>function.h</code>)</p> <pre><code>void function(int argument, bool flag); </code></pre> <p>This function has two variant behaviours, dependening on <code>flag</code>.</p> <p>Early on, in a module (<code>module.h</code>, <code>module.c</code>) I called that function:</p> <pre><code>#include "function.h" function(argument1, true); function(argument2, false); </code></pre> <p>Let's further assume, I want to pass this function into a module, inverting that dependencies:</p> <pre><code>void (* funcPtr)(int argument, bool flag); void setFuncPtr(void (* func)(int argument, bool flag)) { funcPtr = func; } </code></pre> <p>Now I can have in <code>function.c</code>:</p> <pre><code>#include "module.h" setFuncPtr(function); </code></pre> <p>And in <code>module.h</code>:</p> <pre><code>funcPtr(argument1, true); funcPtr(argument2, false); </code></pre> <p>Is there a way to have two pointers, each pointing to the function, but with different, hardcodes values for <code>flag</code>? Like:</p> <pre><code>void (* funcPtrTrue)(int argument, bool flag); void (* funcPtrFals)(int argument, bool flag); /* Or, even better void (* funcPtrTrue)(int argument); void (* funcPtrFals)(int argument); */ void setFuncPtr(void (* func)(int argument, bool flag)) { funcPtrTrue = func(argument, true); funcPtrFalse = func(argument, false); } </code></pre> <p>(I now, this is no correct code, but should illustrated the desired functionality)</p> <p>After Olis proposal, let's complicate things. <code>bool</code> is a typedef in <code>function.h</code>:</p> <pre><code>typedef enum { FALSE, TRUE } bool; </code></pre> <p>Now I have to include <code>function.h</code> again to <code>module.c</code> in order to make it work again.</p> <pre><code>#include "function.h" void functionTrue(int argument) { fktPtr(argument, TRUE); } </code></pre>
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    1. CONope, not possible. A function pointer is an address. It doesn't hold any more information in it, as argument checking is compile-time, not run-time. Use wrappers, like Oli suggested.
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      1. USNikos C.
 

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