这是一个variable arguments的printf,可以像使用库函数一样使用DEBUG_PRINT()。 2、Pasting Tokens/粘贴token/将token和在...上 Each argument passed to a macro is a token, and sometimes it might be expedient to paste arguments together to form a new token. This could come in handy if you have ...
Now, the important thing is that:How Macro arguments evaluate?-"Macro arguments do not evaluate before Macro expansion, they evaluate after the expansion." Consider the example: Example #include<stdio.h>#defineCALC(X,Y)(X*Y)intmain(){printf("%d\n",CALC(1+2,3+4));return0;} ...
Average of 2, 3, 4, 5 = 3.500000 Average of 5, 10, 15 = 10.000000 It should be noted that the functionaverage()has been called twice and each time the first argument represents the total number of variable arguments being passed. Only ellipses are used to pass variable number of argumen...
typedef char * va_list; /* Storage alignment properties -- 堆栈按X对齐 */ #define _AUPBND (sizeof (X) - 1) #define _ADNBND (sizeof (X) - 1) /* Variable argument list macro definitions -- 变参函数内部实现需要用到的宏 */ #define _bnd(X, bnd) (((sizeof (X)) + (bnd)) ...
A macro can be declared to accept a variable number of arguments much as a function can. The syntax for defining the macro is similar to that of a function. Here is an example: #define eprintf(...) fprintf (stderr, __VA_ARGS__) ...
Arguments must be used each time of macro calling. This type of macro seems like a function; hence we can say that this is the"Function Like Macro Definition". Syntax Here, #defineis a pre-processor directive macro_nameis the name of macro ...
带有可变参数的宏(Macros with a Variable Number of Arguments) 在1999年版本的ISO C 标准中,宏可以象函数一样,定义时可以带有可变参数。宏的语法和函数的语法类似。 下面有个例子: 复制代码代码如下: #define debug(format, ...) fprintf (stderr, format, __VA_ARGS__) ...
带有可变参数的宏(Macros with a Variable Number of Arguments) 在1999年版本的ISO C 标准中,宏可以象函数一样,定义时可以带有可变参数。宏的语法和函数的语法类似。 下面有个例子: 复制代码代码如下: #define debug(format, ...) fprintf (stderr, format, __VA_ARGS__) ...
可变参数的宏里的'##'操作说明带有可变参数的宏(Macros with a Variable Number of Arguments) 在1999年版本的ISO C 标准中,宏可以象函数一样,定义时可以带有可变参数。宏的语法和函数的语法类似。下面有个例子: 1 #define debug(format, ...) fprintf (stderr, format, __VA_ARGS__) 这里,'...'指可...
#definepint(int*)pint pa,pb; 本意是定义pa和pb均为int型指针,但实际上变成int* pa,pb;。pa是int型指针,而pb是int型变量。本例中可用typedef来代替define,这样pa和pb就都是int型指针了。 因为宏定义只是简单的字符串代换,在预处理阶段完成,而typedef是在编译时处理的,它不是作简单的代换,而是对类型说明符...