A difficulty of realloc.

Abstract: The following code has an impressive bug in the book Writing Solid Code)

 pbBuf = (char *)realloc(pbBuf, sizeNew); 
 if (pbBuf != NULL){
     /* do something */ 
 }
 

Can you see the bug? It's a serious bug. pbBuf pointed to a legal address, and sizeNew > 0 when the realloc is called.

• Before start to read here, please think about that a while. If you know a bug is here, you may be able to find that.

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• This is a memory leak bug. When the realloc returns NULL. You will lost old valid memory block unless you keep an alias of pbBuf. The book tells us, Do not bury an error code to the valid usable return value. getchar, strdup, malloc, realloc, ... all have not so good interface. I now agree that. But I use now C++ and when the new() failed a memory allocation, then an exception will be thrown. This is a kind of improvement. So, I also recommend to use C++ one. Even though the exception mechanism has another problem, like the shard library bounday, mixing compilers, ....