[問題] while(*p)是啥意思?
這是我在"一步步寫嵌入式操作系統"看到的:
#define UFCON0 ((volatile unsigned int*)(0x50000020))
void helloworld(void) {
const char *p = "helloworld\n";
while (*p) {
*UFCON0 = *p++;
};
while(1);
}
請問這邊的while (*p)是啥意思?
還有為啥while結束要加;?(不是{}後不用加?)
while(1)這邊不就是無線迴圈嗎?
這整個程式在幹嘛?
PS: 我試著用gcc編譯過(main裏面呼叫這函式),
可是run不起來(Segmentation fault (core dumped))
感謝。
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