External Interrupt with STM32 | Example code STM32 with Standard Peripheral Lib

static void EXTILine0_Config(void);
static void EXTILine15_Config(void);

/* Private functions ---------------------------------------------------------*/

/**
  * @brief  Main program
  * @param  None
  * @retval None
  */
int main(void)
{
  /*!< At this stage the microcontroller clock setting is already configured,
       this is done through SystemInit() function which is called from startup
       files (startup_stm32f40xx.s/startup_stm32f427x.s) before to branch to
       application main.
       To reconfigure the default setting of SystemInit() function, refer to
       system_stm32f4xx.c file
     */

  /* Initialize LEDs mounted on EVAL board */
  STM_EVAL_LEDInit(LED1);
  STM_EVAL_LEDInit(LED2);

  /* Configure EXTI Line0 (connected to PA0 pin) in interrupt mode */
  EXTILine0_Config();

  /* Configure EXTI Line15 (connected to PG15 pin) in interrupt mode */
  EXTILine15_Config();

  /* Generate software interrupt: simulate a falling edge applied on EXTI0 line */
  EXTI_GenerateSWInterrupt(EXTI_Line0);

  while (1)
  {
  }
}

/**
  * @brief  Configures EXTI Line0 (connected to PA0 pin) in interrupt mode
  * @param  None
  * @retval None
  */
static void EXTILine0_Config(void)
{
  EXTI_InitTypeDef   EXTI_InitStructure;
  GPIO_InitTypeDef   GPIO_InitStructure;
  NVIC_InitTypeDef   NVIC_InitStructure;

  /* Enable GPIOA clock */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
  /* Enable SYSCFG clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
 
  /* Configure PA0 pin as input floating */
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Connect EXTI Line0 to PA0 pin */
  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0);

  /* Configure EXTI Line0 */
  EXTI_InitStructure.EXTI_Line = EXTI_Line0;
  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising; 
  EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_Init(&EXTI_InitStructure);

  /* Enable and set EXTI Line0 Interrupt to the lowest priority */
  NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0F;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x0F;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}

/**
  * @brief  Configures EXTI Line15 (connected to PG15 pin) in interrupt mode
  * @param  None
  * @retval None
  */
static void EXTILine15_Config(void)
{
  EXTI_InitTypeDef   EXTI_InitStructure;
  GPIO_InitTypeDef   GPIO_InitStructure;
  NVIC_InitTypeDef   NVIC_InitStructure;

  /* Enable GPIOG clock */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOG, ENABLE);
  /* Enable SYSCFG clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
 
  /* Configure PG15 pin as input floating */
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_15;
  GPIO_Init(GPIOG, &GPIO_InitStructure);

  /* Connect EXTI Line15 to PG15 pin */
  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOG, EXTI_PinSource15);

  /* Configure EXTI Line15 */
  EXTI_InitStructure.EXTI_Line = EXTI_Line15;
  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
  EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_Init(&EXTI_InitStructure);

  /* Enable and set EXTI15_10 Interrupt to the lowest priority */
  NVIC_InitStructure.NVIC_IRQChannel = EXTI15_10_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0F;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x0F;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

  NVIC_Init(&NVIC_InitStructure);
}