rt-thread-official/components/libc/compilers/common/extension/fcntl/README.md

Because of the history issue, flags in fcntl.h, such as O_CREAT, have difference types of value. Some OS use hex flags and others use octal flags.

In terms of RT-Thread, Keil, IAR and MSVC use octal flags, which is located in the `tcntl/octal` folder; newlib uses hex flags; musl uses octal flags.
improve libc time and MSVC simulator (#5775) - [libc] 解决由于类unix操作系统发展历史原因fcntl.h定义的标志位在不同编译器中定义不同的问题 - [simulator] 部分宏定义转为全局宏定义以确保vs内置文件可以正确配置 - [simulator] 取消自欺欺人式的警告消除处理方式 - [libc][time] 优化time相关结构体在不同编译器下的包含 2022-04-07 02:24:11 -04:00			`Because of the history issue, flags in fcntl.h, such as O_CREAT, have difference types of value. Some OS use hex flags and others use octal flags.`

			In terms of RT-Thread, Keil, IAR and MSVC use octal flags, which is located in the `tcntl/octal` folder; newlib uses hex flags; musl uses octal flags.