c - 在c中声明十六进制字符 'error: multi-character character constant'

Question

在下面的函数中，我从 UART 读取两个字节的十六进制字符。我正在尝试检测数据的开头，即十六进制字符 FF。编译器给出错误错误:多字符字符常量。我应该如何声明FF？

void getData(void) {
    int i;
    static uint8_t detectedStartChar = 0;
    int buffans[264]; 
    int retchar;

    for (i = 0; i < 264; i++) {
        retchar = getch(UART_0);
        if (retchar == 'DD') {
            detectedStartChar = 1;
            buffans[i] = retchar;
        }
    }
}

Answer 1

正如评论中提到的，修复是:-

if (retchar == 0xff ){ /* compare the value */

if (retchar == '\xff' ){ /* compare the character representation */