C++ name convention

本节对C++ name convention进行描述。

Header file

C++的header file的name convention是不带.h；C++是C的超集，所以它会包含C的header file，对于这种情况，name convention为c***:

C	C++
string.h	cstring
stdlib.h	cstdlib

_t and _type suffix

参考:

• stackoverflow C++ type suffix _t, _type or none

_t suffix

stackoverflow C++ type suffix _t, _type or none:

in C++14 _t suffix is commonly used to indicate an alias template for nested ::type typedef, e.g. X_t<T> stands for typename X<T>::type – Piotr Skotnicki Oct 16 '14 at 9:22

A:

As a C heritage the _t (that used to mean "defined via typedef") syntax has been inherited (they're also SUS/POSIX-reserved in the global namespace).

_type suffix

stackoverflow C++ type suffix _t, _type or none:

It seems _type is more common in template meta-programming (for template class member typedefs), whereas no suffix is used when it is not important for the outside whether the typename is a class or a typedef. For (template) class member types there just seem to be some edge cases when it isn't clear which would be more appropriate. – tmlen Oct 16 '14 at 9:19

A:

there are a few such names (also pointed out in a comment by @jrok): common_type, underlying_type, is_literal_type, true_type, false_type. In the first three, _type is not really a suffix, it's an actual part of the name (e.g. a metafunction to give the common type or the underlying type). With true_type and false_type, it is indeed a suffix (since true and false are reserved words). I would say it's a type which represents a true/false value in the type-based metaprogramming sense.

_t and _v suffix in trait

在 "tartanllama Detection Idiom - A Stopgap for Concepts # Metaprogramming demystified # Type traits and _v and _t suffixes" 段中，对此有着非常好的总结。

tartanllama Detection Idiom - A Stopgap for Concepts # Metaprogramming demystified # Type traits and _v and _t suffixes

A type trait is some template which can be used to get information about characteristics of a type. For example, you can find out if some type is an arithmetic type using std::is_arithmetic:

template <class T>
void foo(T t) {
     static_assert(std::is_arithmetic<T>::value, "Argument must be of an arithmetic type");
}

Type traits either “return” types with a ::type member alias, or values with a ::value alias. _t and _v suffixes are shorthand for these respectively. So std::is_arithmetic_v<T> is the same as std::is_arithmetic<T>::value, std::add_pointer_t<T> is the same as typename std::add_pointer<T>::type1.