A data type used to hold information about variable arguments passed to a variadic function. It is initialized with `va_start`, used with `va_arg`, and cleaned up with `va_end`.
1st Parameter
The `va_list` object to initialize. This object will hold information about the variable arguments.
2nd Parameter Type : T
Represents a placeholder for a specific type (e.g., `int`, `double`, `char *`) used in variadic functions with macros like `va_arg`. The actual type must match the argument being accessed.
2nd Parameter
The name of the last named argument in the function's parameter list. This argument serves as the starting point for accessing the variable arguments.
Read more about parameters of va_start in parameters section
The va_startfunction in C language Initializes a va_list to retrieve the additional arguments passed to the function.
va_start is a macro that initializes the va_list for subsequent use by va_arg and va_end. It must be called before any access to the unnamed arguments. The param argument is the name of the last named parameter in the function definition.
The va_startfunction takes 2
parameters:
•
va_list `ap`: The `va_list` object to initialize. This object will hold information about the variable arguments.
•
T `last`: The name of the last named argument in the function's parameter list. This argument serves as the starting point for accessing the variable arguments.
Initializes the `va_list` object `ap` to access the variable arguments of a variadic function, starting after the last named argument `last`. The behavior is undefined if `va_start` is called without a corresponding `last` argument in the function signature.
The va_start function return value :
None (void function)
Output
This example demonstrates how to use va_start to initialize a va_list in a function that prints a variable number of integers.