Arduino 的新运算符

有人告诉我（特别是在一个答案Arduino 上的 C++ 标准库，以及 Stack Overflow 问题中C++ 字符串和 Arduino 字符串。如何将它们结合起来？)) Arduino 编译器没有实现new操作员。不过，我已经为 Arduino（在 Arduino IDE 中）编写了一个使用它的程序，并且运行良好。

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

void loop() {
    char* array;
    char c;
    unsigned arraySize;

    Serial.write("Enter a 1 digit number.\n");

    do {
        c = Serial.read();
    } while(c < '0' or c > '9');
    arraySize = c-'0';

    Serial.write("You wrote ");
    Serial.write(c);
    Serial.write(".\n");
    Serial.write("Now enter ");
    Serial.write(c);
    Serial.write(" lower-case letters.\n");

    array = new char[arraySize];

    for (unsigned i = 0; i < arraySize;) {
        array[i] = Serial.read();
        if (array[i] >= 'a' and array[i] <= 'z')
            i++;
    }

    Serial.write("You entered: ");

    for (unsigned i = 0; i < arraySize; i++) {
        Serial.write(array[i]);
        Serial.write(" ");
    }
    Serial.write("\n");
}

以下是演示其功能的示例输出：

Enter a 1 digit number.
You wrote 5.
Now enter 5 lower-case letters.
You entered: h e l l o
Enter a 1 digit number.
You wrote 9.
Now enter 9 lower-case letters.
You entered: w a s s u p m a n
Enter a 1 digit number.
You wrote 9.
Now enter 9 lower-case letters.
You entered: h o w y a d o i n
Enter a 1 digit number.
You wrote 4.
Now enter 4 lower-case letters.
You entered: c o o l
Enter a 1 digit number.
You wrote 7.
Now enter 7 lower-case letters.
You entered: i t w o r k s
Enter a 1 digit number.

那为什么我总是听到这个？这些人是错的，还是我只是误解了他们的意思？

new and delete被定义为 Arduino 发行版的一部分：/usr/share/arduino/hardware/arduino/cores/arduino/new.h:

/* Header to define new/delete operators as they aren't provided by avr-gcc by default
   Taken from http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=59453 
 */
#ifndef NEW_H
#define NEW_H

#include <stdlib.h>

void * operator new(size_t size);
void operator delete(void * ptr); 

__extension__ typedef int __guard __attribute__((mode (__DI__)));

extern "C" int __cxa_guard_acquire(__guard *);
extern "C" void __cxa_guard_release (__guard *);
extern "C" void __cxa_guard_abort (__guard *); 

extern "C" void __cxa_pure_virtual(void);

#endif

The new.h包含在Printable.h所以你可以在你的 Arduino 基本包含中得到它。不过，AVR Libc 中并未定义这些运算符。我对这些设计选择的解释：Libc 的人认为这是一个坏主意，而 Arduino 的人则注重易用性：如果你愿意new and delete，请拥有它们。