char* 类型的常量，所以不能用ptr来修改所指向的内容，换句话说，*ptr的值为const，不能修改。但是ptr的声明并不意味着它指向的值实际上就是一个常量，而只是意味着对ptr而言，这个值是常量。实验如下：ptr指向str，而str不是const，可以直接通过str变量来修改str的值，但是确不能通过ptr指针来修改。
在嵌入式系统或微控制器编程中,const uint8_t bootanimationimg[] PROGMEM 可以用于存储动画的帧数据。例如,在Arduino项目中,你可能想要从Flash Memory中读取一个动画的像素数据,并将其发送到LCD显示屏上。使用 PROGMEM 可以避免将大量图像数据存储在RAM中,从而节省宝贵的RAM资源。 cpp // 假设bootanimationimg存储了...
将const uint8_t []转换为std::string可以通过以下方式实现: 使用std::string的构造函数:可以直接使用std::string的构造函数将const uint8_t []转换为std::string。例如: 代码语言:txt 复制 const uint8_t data[] = {65, 66, 67, 0}; // 示例数据 std::string str(reinterpret_cast<const ...
Hey I use the library for a few projects and people reported the same issue, however if I change it I get an error message that uint8 would be wrong. Was there a library update I haven't noticed or why is this making problems? Because right now half of the people will complain that...
(const uint8_t *)buffer16表示将buffer16转换为指向不应用于修改对象的uint8_t字节的指针。buffer16...
data2 points to a string (most likely, I didn't look too deep) of uint8 that are const, which means your code should not try to write to them. You should probably copy that data2 to your own buffer if you don't use it during the callback (it may not be valid after the call...
(const uint8_t *)buffer16表示将buffer16转换为指向不应用于修改对象的uint8_t字节的指针。buffer16...
50 | void beginSSL(const char * host, uint16_t port, const char * url = "/", const uint8_t * fingerprint = NULL, const char * protocol = "arduino"); | ^ exit status 1 invalid conversion from 'const char*' to 'const uint8_t*' {aka 'const unsigned char*'} [-fpermissive] ...
mqtt_display.drawBitmap(85,68,(uint8_t *)BiliBili_1,60,60,MAGENTA); } void loop() { if (!client.connected()) { reconnect(); } client.loop(); } void mediabuttons() { // play mqtt_display.fillScreen(ST77XX_BLACK); mqtt_display.fillRoundRect(30, 160, 78, 60, 8, ST77XX_WH...
uint8_tflag=1; voidtest(void) { while(flag) { //do something } } //interrupt service routine voidisr_test(void) { flag=0; } 如果没使用volatile定义flag,可能在优化后test陷入死循环,因为test里使用的flag并没修改它,开启优化后,编译器可能会固定从某个内存取值。例如: ...