Variable parameters in C Language

 

A Class of functions in c and c ++ contain a list of all uncertain parameters, such as the classic printf (char * format ,...). This article describes how to implement functions with variable-length parameters.

<Stdarg. h> contains a set of macro definitions that define how to traverse the parameter table.

There are four main types:

Va_list: Used to declare a variable. The variable references parameters in the parameter list in sequence, for example, va_list ap. The Suffix list should be a linked list.

Va_start: used to point the variables declared by the ap to the first unnamed parameter. Va_start (ap, the last famous parameter ). The Variable Length Parameter Function must contain a famous parameter.

Va_arg: return the parameter currently pointed to by the ap and ++ ap. Va_arg (ap, type)

Va_end: complete necessary cleanup.

 

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