Errata

There are no page numbers for my copy of this book. The problem is with the "Chapter 1. Summary of Strategies for Optimizng C++ Code: Use a Better Compiler, Use Your Compiler Better" section.

"Compile times are slightly shorter without the optimizer. This was a big deal in the 1990s, but nowadays compilers and computers are so fast that it offers little benefit."

This simply isn't true. Many corporations regularly deploy huge C++ systems and compile time is still a critical issue. I consult on such products for the financial sector, and my colleages and I have a big issues with compile times running into hours. I've also heard from peers working in agile environments where a 15 minute build time is a huge problem.

There are no page numbers for my copy of this book. The error is in the 1st paragraph of the Memory is Not Accessed in Bytes section of Chapter 2.

The sentence:

"Desktop-class processors may fetch 64 bytes at once."

should be:

"Desktop-class processors may fetch 64 bits at once."

"In such a situation, improving
response time from 0.1 second to one millisecond adds virtually no value, even
though it is 1000 times faster."

.1 seconds = 100ms 1ms/100ms is 100x faster not 1000.

"Eliminate Pointer Dereference Using Iterators" describes the efficiency gained by using iterators as "avoiding pointer dereference". In reality most iterators are actually implemented as pointers. The efficiency gained by iterators is not in avoiding the dereference but rather in not having to do pointer arithmetic under the hood. So in example 4-4 calling s[i] is in effect s + i. However when iterators are used this pointer arithmetic is integrated with the increment of the for loop, thereby saving that addition. However technically both example 4-4 and 4-5 still dereference pointers.

code says:
std::vector<int> a(1000000, 0);
...
std::vector<int> b; // b is empty
std::wrap(v,w); // now b has a million entries <-- v,w should be a,b

code snippet essentially uses the wrong variables.