赋字符串给结构体变量

最新推荐文章于 2024-01-02 09:25:40 发布

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最新推荐文章于 2024-01-02 09:25:40 发布

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文章标签：字符串

本文链接：https://blog.youkuaiyun.com/qq_51174802/article/details/120202840

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本文探讨了在ESP32-C3开发中如何正确地将字符数组赋值给sta模式的SSID和密码字段，避免了类型转换错误。通过使用strcpy函数手动复制字符串解决了编译问题，重点在于理解指针和字符串赋值的原理。

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问题

在esp32c3开发中，使用字符数组保存了sta模式需要用到的ssid、password
char sta_ssid[32]=“MST_XIAOMI”
char sta_password[64]=“123456789”

而在进行sta模式配置时如下：

//wifi配置
    wifi_config_t wifi_config = {
        .sta = {
            .ssid = sta_addr,					
            .password = sta_password,					
            /* Setting a password implies station will connect to all security modes including WEP/WPA.
             * However these modes are deprecated and not advisable to be used. Incase your Access point
             * doesn't support WPA2, these mode can be enabled by commenting below line */
	     	.threshold.authmode = WIFI_AUTH_WPA2_PSK,

            .pmf_cfg = {
                .capable = true,
                .required = false
            },
        },
    };

该结构体中变量 .ssid 和 .password 类型如下：
在这里插入图片描述
直接将数组名赋值过来，在编译时报错如下：
（从’char *'初始化’unsigned char’将从指针生成整型，而不需要强制转换）

解析

参考station项目的配置内容如下：

有宏定义：
#define EXAMPLE_ESP_WIFI_SSID “MST_XIAOMI”
#define EXAMPLE_ESP_WIFI_PASS “123456789”

//wifi配置
    wifi_config_t wifi_config = {
        .sta = {
            .ssid = EXAMPLE_ESP_WIFI_SSID,
            .password = EXAMPLE_ESP_WIFI_PASS,
            /* Setting a password implies station will connect to all security modes including WEP/WPA.
             * However these modes are deprecated and not advisable to be used. Incase your Access point
             * doesn't support WPA2, these mode can be enabled by commenting below line */
	     	.threshold.authmode = WIFI_AUTH_WPA2_PSK,

            .pmf_cfg = {
                .capable = true,
                .required = false
            },
        },
    };

即相当于赋值如下：
.ssid = “MST_XIAOMI”
.password= “123456789”

而我赋值如下：
char sta_ssid[32]=“MST_XIAOMI”
char sta_password[64]=“123456789”
.ssid=sta_ssid
.password=sta_password

直接用字符数组名赋值只是将数组首地址给出，并不给出数组中的字符串，所以编译出错，不能以这种形式赋值

于是改变为：

//wifi配置
    wifi_config_t wifi_config = {
        .sta = {
          //  .ssid = sta_addr,					//STA_ESP_WIFI_SSID,
          //  .password = sta_password,			//STA_ESP_WIFI_PASS,		
            /* Setting a password implies station will connect to all security modes including WEP/WPA.
             * However these modes are deprecated and not advisable to be used. Incase your Access point
             * doesn't support WPA2, these mode can be enabled by commenting below line */
	     	.threshold.authmode = WIFI_AUTH_WPA2_PSK,

            .pmf_cfg = {
                .capable = true,
                .required = false
            },
        },
    };
	strcpy((char *)wifi_config.sta.ssid,sta_addr);
	strcpy((char *)wifi_config.sta.password,sta_password);

采用strcpy 来赋值字符串，且第一个参数要强转为char *,否则报错
（“strcpy”的传递参数1中的指针目标的符号不同）
在这里插入图片描述