背景:单片机开发过程中,我在函数体内(begin_face_record)定义了一个局部变量data_length,在使用的时候,该局部变量一直别改变,每次调用其他函数,例如c库里面的函数memcpy,不知什么情况data_length值就会被改变。
1、源码分析
void main(void)
{
init_gpio();
init_face();
face_power_up();
begin_face_record(1,"ZHANG SAN");
}
void begin_face_record(uint8_t admin,INT8 user_name[USER_NAME_SIZE])
{
uint16_t data_length = 0;
//uint16_t i = 0;
UART_Packet *uart_packet;
S_MSG_ENROLL_DATA xdata enroll_data;
enroll_data.admin = admin;
memcpy(enroll_data.user_name,user_name,strlen(user_name));
enroll_data.face_direction = FACE_DIRECTION_MIDDLE;
enroll_data.timeout = TIMEOUT;
//i = data_length;
data_length = strlen(user_name);
//strlen(enroll_data.user_name)+sizeof(enroll_data.face_direction)+sizeof(enroll_data.timeout);
uart_packet = allocatePacket(ID_ENROLL,&enroll_data