What is __ Va_args __ C++?
fprintf (stderr, __VA_ARGS__) This kind of macro is called variadic. When the macro is invoked, all the tokens in its argument list after the last named argument (this macro has none), including any commas, become the variable argument.
How do you declare a variadic function?
To declare a variadic function, an ellipsis appears after the list of parameters, e.g. int printf(const char* format…);, which may be preceded by an optional comma. See Variadic arguments for additional detail on the syntax, automatic argument conversions and the alternatives.
What is __va_args __?
Here also we have to include ellipsis, The ‘__VA_ARGS__’ is used to handle variable length arguments. Concatenation operator ‘##’ is used to concatenate the variable arguments. In this example, the Macro will take variable length argument like the printf() or scanf() function.
How many arguments macro can have?
For portability, you should not have more than 31 parameters for a macro. The parameter list may end with an ellipsis (…).
What is recursive macro expansion?
21.5. 1 Macro Expansion Is Recursive When text contains other macros, those other macros are also expanded. This process is recursive and continues until all macros have been expanded.
What is a variadic in C?
Variadic functions are functions that can take a variable number of arguments. In C programming, a variadic function adds flexibility to the program. It takes one fixed argument and then any number of arguments can be passed.
What is variadic parameters in go?
In Golang, a function that can be called with a variable argument list is known as a variadic function. One can pass zero or more arguments in the variadic function. If the last parameter of a function definition is prefixed by ellipsis …, then the function can accept any number of arguments for that parameter.
What does ## mean in C?
## is Token Pasting Operator. The double-number-sign or “token-pasting” operator (##), which is sometimes called the “merging” operator, is used in both object-like and function-like macros.
What is a Va_list?
va_list is a complete object type suitable for holding the information needed by the macros va_start, va_copy, va_arg, and va_end. If a va_list instance is created, passed to another function, and used via va_arg in that function, then any subsequent use in the calling function should be preceded by a call to va_end.
Can macro return a value?
Macros just perform textual substitution. They can’t return anything – they are not functions.
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