Here are a few title options, keeping in mind the question format and addressing the core of the article: * Why Does Dereferencing a Null Pointer in C Not Throw an Exception? * How Do I Handle Unde

How to Handle Undefined Behavior in C

In C , dereferencing null pointers doesn't trigger an exception; it results in undefined behavior. This behavior often manifests as a segmentation fault or crash.

Consider the following code:

<code class="cpp">try {
  int* p = nullptr;
  *p = 1;
} catch (...) {
  cout << "null pointer." << endl;
}</code>

This attempt to catch the "null pointer exception" won't work because null pointer dereferencing isn't an exception in C . Instead, it evokes undefined behavior.

Solution: Manual Detection and Exception Throwing

In C , it's the programmer's responsibility to manually detect null pointers and throw an exception if encountered. This can be achieved with an explicit check before dereferencing:

<code class="cpp">if (p != nullptr) {
  *p = 1;
} else {
  throw invalid_argument("null pointer");
}</code>

By explicitly throwing an exception, it can be caught in a try-catch block.

Note on C Implementations

Some C implementations, such as Visual C , may have features to "convert" system/hardware exceptions into C exceptions. However, this non-standard functionality comes with performance penalties and shouldn't be relied upon.

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