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This article mainly explains the meaning of "hanging pointer" and "wild pointer" in C language. The content of the explanation in this article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought. Let's study and learn what the "hanging pointer" and "wild pointer" of C language mean.

1 A pointer in the C language can point to a piece of memory, and if the memory is later reclaimed (freed) by the operating system, but the pointer still points to the memory, then the pointer is a "dangling pointer". The following C code is an example, see: void * p = malloc (size); assert (p); free (p); / / now p is a "dangling pointer"

The "dangling pointer" in C language can cause unpredictable errors, and once such errors occur, it is difficult to locate. This is because after free (p), the p pointer still points to the previously allocated memory, and if the memory is temporarily accessible by the program without causing conflicts, then using p later will not cause an error. The hardest bug to debug is always the bug that can't be easily reproduced, right?

Therefore, in the actual C language program development, in order to avoid unpredictable errors caused by "dangling pointers", after releasing memory, pointer p is often assigned to NULL: void * p = malloc (size); assert (p); free (p); / / avoid "dangling pointers" p = NULL

The advantage of this is that once the released pointer p is used again, a "segment error" will be immediately raised, and the programmer will immediately know that the C code should be modified. 2. The "dangling pointer" above the wild pointer is a pointer to the released memory, while the "wild pointer" is an uncertain pointer. "wild pointer" most often comes from an uninitialized pointer, such as the following C code: void * p; / / at this time p is a "wild pointer".

Because the "wild pointer" may point to any memory segment, it may damage normal data or cause other unknown errors, so the "wild pointer" in the C language is even more harmful than the "dangling pointer". In the actual C language program development, when defining pointers, we should generally try to avoid the emergence of "wild pointers" (giving initial values): void * p = NULL;void * data = malloc (size); these two points are more important contents of C language. I hope you must pay attention to them when coding.

Thank you for your reading, the above is the content of "what is the meaning of" hanging pointer "and" wild pointer "in C language? after the study of this article, I believe you have a deeper understanding of the meaning of" hanging pointer "and" wild pointer "in C language, and the specific use still needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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