C Standard Library 简明教程

C Library - <stdarg.h>

stdarg.h 标头定义了一个变量类型 va_list 和三个宏，当参数数量未知（即，可变数量参数）时，可用于获取函数中参数。

The stdarg.h header defines a variable type va_list and three macros which can be used to get the arguments in a function when the number of arguments are not known i.e. variable number of arguments.

可变参数函数用省略号（,…）定义，位于参数列表末尾。

A function of variable arguments is defined with the ellipsis (,…) at the end of the parameter list.

Library Variables

以下是在标头 stdarg.h 中定义的变量类型 −

Following is the variable type defined in the header stdarg.h −

Sr.No.

Variable & Description

va_list This is a type suitable for holding information needed by the three macros va_start(), va_arg() and va_end().

Library Macros

以下是在标头 stdarg.h 中定义的宏 −

Following are the macros defined in the header stdarg.h −

Sr.No.	Macro & Description
1	void va_start(va_list ap, parmN)This macro enables access to variadic function arguments.
2	type va_arg(va_list ap, type)This macro retrieves the next argument in the parameter list of the function with type type.
3	void va_end(va_list ap)This macro allows to end traversal of the variadic function arguments.
4	void va_copy( va_list dest, va_list src )This macro makes a copy of the variadic function arguments.