语言环境设置会导致printf中的% l s格式说明符调用wcsrtombs函数以便于将宽字符的参数字符串转换成依赖语言环境的多字节编码。

The locale setting will cause the % ls format specifier in printf to call the wcsrtombs function in order to convert the wide character argument string into the locale-dependent multi-byte encoding.

youdao

Only the operating system has controlling of byte zero NULL in the computer's RAM and so if a function ever returns null, aka zero, well, something must have gone wrong because that can't possibly belong to me that memory because by human convention zero is owned by the operating system; not by a program I wrote.

只用操作系统在内存中能够控制,字节0，并且如果一个函数返回，或者说0，好的，可能出错了,因为那可能是不属于我的内存,因为惯例上，0是由操作系统拥有的,而不是由我的程序拥有的。

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