在代码中访问 Makefile 变量? [英] Accessing Makefile variables in code?

问题描述

更新进度

抱歉，我忘记将此问题指定为 Arduino 问题.我只是假设这是一个预处理器问题，与正在执行的平台无关.

我正在使用 Arduino-Make 并尝试传入 USERNAME 和 PASSWORD

BOARD_TAG = mega2560CPPFLAGS = -DUSERNAME="$(USERNAME)" -DPASSWORD="$(PASSWORD)"包括 $(ARDMK_DIR)/Arduino.mk

命令行:

设置 USERNAME="HELLO" PASSWORD="WORLD"

代码:

void setup() {Serial.begin(9600);字符串 auth_raw2(用户名:密码)；Serial.println(auth_raw2);}无效循环(){}

我收到此错误:

macro.ino:10:29: 错误:在嵌套名称说明符中找到:"，预期为::"macro.ino:10:20: 错误:HELLO"尚未声明

解决方案

根据 Arduino 网站上的文献:>

在构造函数中连接 "会产生不可预测的结果，因为在您开始连接不同的数据类型.为获得最佳结果，请在连接字符串之前对其进行初始化."

<小时>

就您传递给 makefile 的变量而言，语法是正确的，用于定义这些变量的命令行 -D 也是有效的.但是，正如文档所指出的，在传递给构造函数时应该避免混合整数和字符串，尽管首先构造字符串然后连接值是完全有效的.

UPDATED PROGRESS

I am sorry I forgot to specify this question as an Arduino question. I just assumed that it's a preprocessor problem which is kind of independent of what platform this is being executed on.

I am using Arduino-Make and I am trying to pass in USERNAME and PASSWORD

BOARD_TAG    = mega2560
CPPFLAGS     = -DUSERNAME="$(USERNAME)" -DPASSWORD="$(PASSWORD)"
include $(ARDMK_DIR)/Arduino.mk

Command line:

make USERNAME="HELLO" PASSWORD="WORLD"

Code:

void setup() {
  Serial.begin(9600);

  String auth_raw2(USERNAME : PASSWORD);
  Serial.println(auth_raw2);
}


void loop() {}

I am getting this error:

macro.ino:10:29: error: found ‘:’ in nested-name-specifier, expected ‘::’
macro.ino:10:20: error: ‘HELLO’ has not been declared

解决方案

According to the literature at Arduino's Site:

Concatenating in a constructor "gives unpredictable results because 'auth_raw' never got an initial value before you started concatenating different data types. For best results, initialize your Strings before you concatenate them."

---

As far as the variables you are passing to your makefile are concerned, the syntax is correct, and the commandline -D to define those variables is as well valid. However, as the documentation points out, you should avoid mixing integers and strings when passing to a constructor, though it would be perfectly valid to construct the String first, and then concatenate the values.

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