event-endian-test.c

#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>

uint8_t event1(int32_t* param) {
  uint8_t data = (uint8_t)*param;

  printf("%"PRId8"\n", data);
}

uint8_t event2(int32_t* param) {
  uint8_t data = *(uint8_t*)param;

  printf("%"PRId8"\n", data);
}

int main(int argc, char* argv[]) {
  uint8_t data = 96;

  int32_t param1 = (int32_t)data;
  int32_t param2 = 0xdeadbeef;  // 検証のために適当に値を埋めておく
  *( (uint8_t*)&param2 ) = data;

  // 正しい使い方
  event1(&param1);
  event2(&param2);

  // 誤った使い方
  event1(&param2);
  event2(&param1);

  return EXIT_SUCCESS;
}