POSIX表示可移植操作系统接口（Portable Operating System Interface of UNIX，缩写为 POSIX ），POSIX标准定义了操作系统应该为应用程序提供的接口标准。
posix函数（可移植操作系统接口）
- posix_access()
- Determineaccessibilityofafile
- posix_ctermid()
- Getpathnameofcontrollingterminal
- posix_errno()
- 别名posix_get_last_error()
- posix_get_last_error()
- Retrievetheerrornumbersetbythelastposixfunctionthatfailed
- posix_getcwd()
- Pathnameofcurrentdirectory
- posix_getegid()
- ReturntheeffectivegroupIDofthecurrentprocess
- posix_geteuid()
- ReturntheeffectiveuserIDofthecurrentprocess
- posix_getgid()
- ReturntherealgroupIDofthecurrentprocess
- posix_getgrgid()
- Returninfoaboutagroupbygroupid
- posix_getgrnam()
- Returninfoaboutagroupbyname
- posix_getgroups()
- Returnthegroupsetofthecurrentprocess
- posix_getlogin()
- Returnloginname
- posix_getpgid()
- Getprocessgroupidforjobcontrol
- posix_getpgrp()
- Returnthecurrentprocessgroupidentifier
- posix_getpid()
- 返回当前进程id
- posix_getppid()
- Returntheparentprocessidentifier
- posix_getpwnam()
- 按用户名返回有关用户的信息
- posix_getpwuid()
- Returninfoaboutauserbyuserid
- posix_getrlimit()
- Returninfoaboutsystemresourcelimits
- posix_getsid()
- Getthecurrentsidoftheprocess
- posix_getuid()
- ReturntherealuserIDofthecurrentprocess
- posix_initgroups()
- Calculatethegroupaccesslist
- posix_isatty()
- Determineifafiledescriptorisaninteractiveterminal
- posix_kill()
- Sendasignaltoaprocess
- posix_mkfifo()
- Createafifospecialfile(anamedpipe)
- posix_mknod()
- Createaspecialorordinaryfile(POSIX.1)
- posix_setegid()
- SettheeffectiveGIDofthecurrentprocess
- posix_seteuid()
- SettheeffectiveUIDofthecurrentprocess
- posix_setgid()
- SettheGIDofthecurrentprocess
- posix_setpgid()
- Setprocessgroupidforjobcontrol
- posix_setrlimit()php7
- Setsystemresourcelimits
- posix_setsid()
- Makethecurrentprocessasessionleader
- posix_setuid()
- 设置当前进程的UID
- posix_strerror()
- Retrievethesystemerrormessageassociatedwiththegivenerrno
- posix_times()
- Getprocesstimes
- posix_ttyname()
- Determineterminaldevicename
- posix_uname()
- Getsystemname