Most C preprocessor features are inactive unless you give specific commands to request their use. (Preprocessor commands are lines starting with`#'; see sectionPreprocessor Commands). But there are three transformations that the preprocessor always makes on all the input it receives, even in the ab...
重要的是它只能在预处理器(preprocessor)中使用。 #操作符用于将标记(token)转换为字符串。 例如: #(a ## b)变成#ab,再变成"ab" 因此,h(f(1,2))变成"f(1,2)" 请注意#和##是两个不同的操作符。 ##预处理器操作符提供了在宏展开期间连接实际参数的方法。如果替换文本中的参数与##相邻,则将该参数...
C语言宏定义详解 在C语言中,宏定义是一种强大的预处理器功能,用于在编译之前对代码进行替换和条件编译。宏定义通过预处理器指令进行定义和使用,能够使代码更加灵活和可维护。本文将对C语言中的宏定义进行全面的讲解,包括各种相关的预处理器指令及其用法。 1. 宏定义关键词总览 2.#define #define指令用于定义宏,可...
1、在一个预处理器宏中的参数前面使用一个#,预处理器会把这个参数转换为一个字符数组。(原文:When you put a # before an argument in a preprocessor macro, the preprocessor turns that argument into a character array. This, combined with the fact that character arrays with no intervening punctuation ...
// preprocessor_token_pasting.cpp #include <stdio.h> #define paster( n ) printf_s( "token" #n " = %d", token##n ) int token9 = 9; int main() { paster(9); } 运行结果: token9 = 9 另外,如果##后的参数本身也是一个宏的话,##会阻止这个宏的展开。
X(Blue)// Define an enum:#define X(name) COLOR_ ##name,enumColor{COLORSCOLOR_COUNT};#undef X// Define a string table:#define X(name) #name,constchar*gColorNames[COLOR_COUNT+1]={COLORS""};#undef X After the preprocessor has run, that code will look like: ...
Mat*_*sel 2 c string-literals c-preprocessor 我有一个 C 函数,用于格式化具有以下签名的字符串:int string_format ( char* dst , const char* fmt , ... ); Run Code Online (Sandbox Code Playgroud) 我通常这样称呼它:char buf[20]; const char* name = "Jeff"; string_format ( buf , "...
C语言基础,使用预处理器:#define可以在程序中定义一个常量,它在编译时会被替换为其对应的值。使用**const**关键字:const关键字用于
STRINGIFY()is a predefined macro that takes one argument, removes any leading and trailing whitespace, reduces each internal whitespace sequence to a single space character and produces a valid OCaml string literal. For example, #defineTRACE(f)Printf.printf">>> %s\n"STRINGIFY(f); fTRACE(print_...
STRINGIFY()is a predefined macro that takes one argument, removes any leading and trailing whitespace, reduces each internal whitespace sequence to a single space character and produces a valid OCaml string literal. For example, #defineTRACE(f)Printf.printf">>> %s\n"STRINGIFY(f); fTRACE(print_...