How to pass macro arguments to a macro function?

How to pass macro arguments to a macro function?

How do I pass macro arguments along with another integer variable to a macro function? Macro arguments are not expanded when the macro call is parsed.

Can a macro be left out of the preprocessor?

You can leave macro arguments empty; this is not an error to the preprocessor (but many macros will then expand to invalid code). You cannot leave out arguments entirely; if a macro takes two arguments, there must be exactly one comma at the top level of its argument list.

What do I need to invoke a macro in C?

The parameters must be valid C identifiers, separated by commas and optionally whitespace. To invoke a macro that takes arguments, you write the name of the macro followed by a list of actual arguments in parentheses, separated by commas.

When do you change the number of arguments in a macro?

The number of arguments you give must match the number of parameters in the macro definition. When the macro is expanded, each use of a parameter in its body is replaced by the tokens of the corresponding argument. (You need not use all of the parameters in the macro body.)

Where do you run the last macro in emacswiki?

Actually, although it’s good to learn this general rule, there is a shortcut for just applying the last-defined keyboard macro to each of the lines of a region: Or to be more precise (from the documentation of the command): For each complete line between point and mark, move to the beginning of the line, and run the last keyboard macro.

When to stop defining macros on the keyboard?

What’s important here is to stop defining the macro at a similar position to where you started it – so that you are in a position to execute it again, after it executes. This is a general rule that you will often follow when defining keyboard macros: try to make them executable N times in a row.

What is the C-x q macro in Emacs?

You can use ‘C-x q’ (command ‘kbd-macro-query’) to make Emacs pause and query the user at a certain point during keyboard macro execution. C-x q runs the command kbd-macro-query which is an interactive autoloaded Lisp function in ` macros ‘.

Are there default arguments for macros in C?

Since C didn’t have overloading and default arguments for functions, it certainly didn’t have them for macros. So to answer your question: no, those features don’t exist for macros. Your only option is to define multiple macros with different names (or not use macros at all).

How does choose from ARG count macro work?

CHOOSE_FROM_ARG_COUNT (NO_ARG_EXPANDER __VA_ARGS__ ()) As the macro name suggests, we are to count number of arguments later. Here comes another trick: the preprocessor only does simple text replacement. It infers the number of arguments of a macro call merely from the number of commas it sees inside the parentheses.

How is a macro similar to a function in C?

This macro is similar to a function call in C programming language. In this, a function name is defined with arguments passed to the function. In the above example, we can function named “ADD” is defined to perform the addition of two numbers “p” and “q”.