APUE学习笔记 Chapter 2 . Unix Standardization and Implementations

1.Unix 的标准

     1.1 ISO C 

     1.2 POSIX( Poratble Operationg System Interface )

               POSIX包含了ISO C中的标准程序

     1.3 Single Unix Specification

2.Unix的实现

     2.1 Unix SystemV Release 4 , AT&T's Unix System Laboratories 

     2.2 4.4BSD , Berkeley Software Distribution

     2.3 FreeBSD, Based on 4.4BSD-Lite

     2.4 Linux

     2.5 Mac OS X ,  a combination of Mach Kernel and the FreeBSD Operationg system

     2.6 Solaris, Based on System V Release 4

3.Limits

      3.1 Compile-time limits，定义于头文件中，程序可以通过头文件进行判定。

      3.2 Runtime limits，需要程序动态调用函数去获得相关的限制值 

              3.2.1 与文件和目录无关   sysconf

              3.2.2 与文件和目录有关   pathconf/fpathconf