关于结构体初始化
最后更新于：2022-04-01 14:51:09
我们一般见的结构体初始化有两种：
~~~
typedef struct
{
uint32_t I2C_ClockSpeed; /*!< Specifies the clock frequency.
This parameter must be set to a value lower than 400kHz */
uint16_t I2C_Mode; /*!< Specifies the I2C mode.
This parameter can be a value of @ref I2C_mode */
uint16_t I2C_DutyCycle; /*!< Specifies the I2C fast mode duty cycle.
This parameter can be a value of @ref I2C_duty_cycle_in_fast_mode */
uint16_t I2C_OwnAddress1; /*!< Specifies the first device own address.
This parameter can be a 7-bit or 10-bit address. */
uint16_t I2C_Ack; /*!< Enables or disables the acknowledgement.
This parameter can be a value of @ref I2C_acknowledgement */
uint16_t I2C_AcknowledgedAddress; /*!< Specifies if 7-bit or 10-bit address is acknowledged.
This parameter can be a value of @ref I2C_acknowledged_address */
}I2C_InitTypeDef;
~~~
比如这个结构体，我们一般这样初始化：
~~~
I2C_InitTypeDef i2c;
i2c.I2C_Ack = I2C_Ack_Enable;
i2c.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
i2c.I2C_ClockSpeed = clock*1000;
i2c.I2C_DutyCycle = I2C_DutyCycle_2;
i2c.I2C_Mode = I2C_Mode_I2C;
i2c.I2C_OwnAddress1 = addr;
~~~
~~~
I2C_InitTypeDef i2c = {
I2C_Ack_Enable,
I2C_AcknowledgedAddress_7bit,
clock*1000,
I2C_DutyCycle_2,
I2C_Mode_I2C,
addr};
~~~
希望大家不要纠结我这个结构体变量的顺序，肯定错了，我只是说下有这种方法！
但是在linux内核里面有这样一种初始化方法：
~~~
I2C_InitTypeDef i2c = {
.I2C_Ack = I2C_Ack_Enable ,
.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit,
.I2C_ClockSpeed = 40000,
.I2C_DutyCycle = I2C_DutyCycle_2,
.I2C_Mode = I2C_Mode_I2C ,
.I2C_OwnAddress1 = 0x0a
};
~~~
但是在keil里面默认是不可以用这种方法初始化的，他属于C99的标准，但是keil默认是C90的标准！
如果需要这样用的话，或者你拿到的工程代码里面有这样定义的，我们可以这样设置就可以了！
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