Technology & Computing

What is __ Va_args __?

By: Sebastian OkolowskiUpdated: February 24, 2021

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The dots are called, together with the __VA_ARGS__ , variadic macros. When the macro is invoked, all the tokens in its argument list [], including any commas, become the variable argument. This sequence of tokens replaces the identifier VA_ARGS in the macro body wherever it appears.

Also to know is, what is a C++ macro?

A macro is a fragment of code which has been given a name. Whenever the name is used, it is replaced by the contents of the macro. However, the preprocessor operator defined (see Defined) can never be defined as a macro, and C++'s named operators (see C++ Named Operators) cannot be macros when you are compiling C++.

What is Variadic function in C?

In mathematics and in computer programming, a variadic function is a function of indefinite arity, i.e., one which accepts a variable number of arguments. Support for variadic functions differs widely among programming languages.

What is __ LINE __ in C?

__LINE__ is a preprocessor macro that expands to current line number in the source file, as an integer. __LINE__ is useful when generating log statements, error messages intended for programmers, when throwing exceptions, or when writing debugging code.

What is ## operator in C?

The '##' pre-processing operator performs token pasting. When a macro is expanded, the two tokens on either side of each '##' operator are combined into a single token, which then replaces the '##' and the two original tokens in the macro expansion.

Related

Is #include a macro?

It doesn't behave exactly like a macro would, but it can achieve some pretty macro-like results, since #include basically just dumps the contents of one file into another.

Why are macros bad?

Macros are just like any other tool - a hammer used in a murder is not evil because it's a hammer. It is evil in the way the person uses it in that way. You can not debug macros. Macro expansion can lead to strange side effects.

What is a macro in C++ and example?

Macros: Macros are a piece of code in a program which is given some name. Whenever this name is encountered by the compiler the compiler replaces the name with the actual piece of code. The '#define' directive is used to define a macro.

What is macro and its types?

In general, there are two types of macros: Executive. These macros generate either code or data that is incorporated into the program being assembled. Generally, an executable instruction is generated. Declarative. These macros produce information used by the assembly process while generating code.

Why macro is used in C?

One reason macros are used is performance. They are a way of eliminating function call overhead because they are always expanded in-line, unlike the "inline" keyword which is an often-ignored hint to the compiler, and didn't even exist (in the standard) prior to C99.

Is a macro a script?

3 Answers. Basically the difference is just one of degree. A script tends to be a lot more formally defined, with a well-defined scripting language behind it, while a macro is usually something more simple and ad-hoc.

How long can a macro name be?

Macro names cannot be longer than 255 characters.

What is macro explain with example?

noun. The definition of a macro is one command on the computer that performs many commands at once. An example of a macro is using Excel VBA to create multi function commands in the Microsoft program Excel.

What is a macro programming?

A macro (which stands for "macroinstruction") is a programmable pattern which translates a certain sequence of input into a preset sequence of output. Macros can be used to make tasks less repetitive by representing a complicated sequence of keystrokes, mouse movements, commands, or other types of input.

Can macros be declared as templates?

Macros and templates are two separate systems without connections between each other. Macros operate on C preprocessor, using basic text substitution. However they're separate subsystems, meaning there can't be a “template macros”.

How many types of macros are there in C++?

How many types of macros are there in c++? Explanation: There are two types of macros. They are object-like and function-like.

What is preprocessor with example?

In computer science, a preprocessor is a program that processes its input data to produce output that is used as input to another program. A common example from computer programming is the processing performed on source code before the next step of compilation.

What is a macro for gaming?

These keys are sometimes used by gamers as rapid-fire buttons, for an edge over the opponent. Simply put, the macro key is a shortcut of key sequences. A key sequence is a series of keyboard keystrokes, mouse actions, or menu actions that are bound to a command.