Declarations in C++
Contents
Declarations in C++¶
I used to spend a lot of time reading and watching conferences on the C++ programming language, and learned a lot about efficiently declaring functions in the modern C++20 compiler. In these notes I hope to explain my understanding of different concepts in declarations.
Table of Contents¶
Method = 0¶
Pure virtual
Constructor or destructor = default¶
Using noexcept¶
volatile¶
Compilers often try to make many optimizations to the written code. An example is, if no attempt is made to modify some integer num, it may be try to change
while(num == 0) {
// ...
}
to just
while (true) {
// ...
}
to save having to retrieve and make the comparison (up to two operations). The compiler doesn’t always ‘see’ all the code though, and a modification to num may be made outside of the code (e.g. in asynchronous or multi-threaded code). In this case, we can use the volatile keyword to tell the compiler not to optimize code involving this value
volatile int num = 0;
Note that structs declared as volatile extends to all of the members also (see a SO thread here).