What is POSIX?－OpenIndiana & ZFS

POSIX這個詞挺常聽說的，但是真實的代表什麼呢?

全名為「Portable Operating System Interface」，意思就是一個介面規定，這樣說起來也是有點抽象，那將清單列出來看過之後，應該就能體會了！

清單如下：

POSIX.1 function calls

Function	POSIX Description
`access`	Tests for file accessibility
`alarm`	Schedules an alarm
`asctime`	Converts a time structure to a string
`cfgetispeed`	Reads terminal input baud rate
`cfgetospeed`	Reads terminal output baud rate
`cfsetispeed`	Sets terminal input baud rate
`cfsetospeed`	Sets terminal output baud rate
`chdir`	Changes current working directory
`chmod`	Changes file mode
`chown`	Changes owner and/or group of a file
`close`	Closes a file
`closedir`	Ends directory read operation
`creat`	Creates a new file or rewrites an existing one
`ctermid`	Generates terminal pathname
`cuserid`	Gets user name
`dup`	Duplicates an open file descriptor
`dup2`	Duplicates an open file descriptor
`execl`	Executes a file
`execle`	Executes a file
`execlp`	Executes a file
`execv`	Executes a file
`execve`	Executes a file
`execvp`	Executes a file
`_exit`	Terminates a process
`fcntl`	Manipulates an open file descriptor
`fdopen`	Opens a stream on a file descriptor
`fork`	Creates a process
`fpathconf`	Gets configuration variable for an open file
`fstat`	Gets file status
`getcwd`	Gets current working directory
`getegid`	Gets effective group ID
`getenv`	Gets environment variable
`geteuid`	Gets effective user ID
`getgid`	Gets real group ID
`getgrgid`	Reads groups database based on group ID
`getgrnam`	Reads groups database based on group name
`getgroups`	Gets supplementary group IDs
`getlogin`	Gets user name
`getpgrp`	Gets process group ID
`getpid`	Gets process ID
`getppid`	Gets parent process ID
`getpwnam`	Reads user database based on user name
`getpwuid`	Reads user database based on user ID
`getuid`	Gets real user ID
`isatty`	Determines if a file descriptor is associated with a terminal
`kill`	Sends a kill signal to a process
`link`	Creates a link to a file
`longjmp`	Restores the calling environment
`lseek`	Repositions read/write file offset
`mkdir`	Makes a directory
`mkfifo`	Makes a FIFO special file
`open`	Opens a file
`opendir`	Opens a directory
`pathconf`	Gets configuration variables for a path
`pause`	Suspends a process execution
`pipe`	Creates an interprocess channel
`read`	Reads from a file
`readdir`	Reads a directory
`rename`	Renames a file
`rewinddir`	Resets the `readdir()` pointer
`rmdir`	Removes a directory
`setgid`	Sets group ID
`setjmp`	Saves the calling environment for use by `longjmp()`
`setlocale`	Sets or queries a program's locale
`setpgid`	Sets a process group ID for job control
`setuid`	Sets the user ID
`sigaction`	Examines and changes signal action
`sigaddset`	Adds a signal to a signal set
`sigdelset`	Removes a signal to a signal set
`sigemptyset`	Creates an empty signal set
`sigfillset`	Creates a full set of signals
`sigismember`	Tests a signal for a selected member
`siglongjmp`	Goes to and restores signal mask
`sigpending`	Examines pending signals
`sigprocmask`	Examines and changes blocked signals
`sigsetjmp`	Saves state for `siglongjmp()`
`sigsuspend`	Waits for a signal
`sleep`	Delays process execution
`stat`	Gets information about a file
`sysconf`	Gets system configuration information
`tcdrain`	Waits for all output to be transmitted to the terminal
`tcflow`	Suspends/restarts terminal output
`tcflush`	Discards terminal data
`tcgetattr`	Gets terminal attributes
`tcgetpgrp`	Gets foreground process group ID
`tcsendbreak`	Sends a break to a terminal
`tcsetattr`	Sets terminal attributes
`tcsetpgrp`	Sets foreground process group ID
`time`	Determines the current calendar time
`times`	Gets process times
`ttyname`	Determines a terminal pathname
`tzset`	Sets the timezone from environment variables
`umask`	Sets the file creation mask
`uname`	Gets system name
`unlink`	Removes a directory entry
`utime`	Sets file access and modification times
`waitpid`	Waits for process termination
`write`	Writes to a file