C中函数传入参数不确定问题

va_list: This type is used as a parameter for the macros defined incstdarg to retrieve the additional arguments of a function.

Each compiler may implement this type in its own way. It is only intended to be used as the type for the object used as first argument for theva_start, va_arg and va_end macros.

va_start is in charge of initializing an object of this type, so that subsequent calls tova_arg with it retrieve the additional arguments passed to the function.

Before a function that has initialized a va_list object with va_start returns, theva_end shall be executed.

 

example:

/* va_arg example */ #include <stdio.h> #include <stdarg.h> int FindMax ( int amount, ...) { int i,val,greater; va_list vl; va_start(vl,amount); greater=va_arg(vl,int); for (i=1;i<amount;i++) { val=va_arg(vl,int); greater=(greater>val)?greater:val; } va_end(vl); return greater; } int main () { int m; m= FindMax (7,702,422,631,834,892,104,772); printf ("The greatest one is: %d\n",m); return 0; }