UB07

Author: Tianlin Xiao.

Content

An identifier, comment, string literal, character constant, or header name contains an invalid multibyte character or does not begin and end in the initial shift state (5.2.1.1).

Description

如果在标识符、注释、字符串字面量、字符常量、头文件名使用了非 ASCII 字符，比如来自不同语言或编码系统的字符，就会导致编译器或解释器出现问题。

Code

#include <stdio.h>
int main() {
    int a哈 =1;
    printf("%d\n",a哈);
    return 0;
}

Configuration

Configuration 1.

MSVC version 1929

Configuration 2.

gcc version 8.1.0 
Target: x86_64-w64-mingw32

Result of Different Configuration

Configuration 1.

- Compilation successful
- Output:1

Configuration 2.

4.c:3:6: error: stray '\345' in program
 int a?1;31mm^
4.c:3:7: error: stray '\223' in program
 int a錷01;31m^
4.c:3:8: error: stray '\210' in program
 int a?1;31mmm =1;
        ^
4.c:4:16: error: stray '\345' in program
 printf("%d\n",a?1;31mm^
4.c:4:17: error: stray '\223' in program
 printf("%d\n",a錷01;31m^
4.c:4:18: error: stray '\210' in program
 printf("%d\n",a?1;31mmm);