STM32 Keil：warning: #223-D: function "LED_Init" declared implicitly

#include "stm32f10x.h"
#include "led.h"
int main()
{
LED_Init();

while(1)
{
GPIO_SetBits(GPIOD,GPIO_Pin_6);
}

}

运行时警告：warning:  #223-D: function "LED_Init" declared implicitly

解决：在头文件下要声明函数 void LED_Init(void);就可以了。