POSIX
- posix_access - Determine accessibility of a file
- posix_ctermid - Get path name of controlling terminal
- posix_errno - Alias of <function>posix_get_last_error</function>
- posix_get_last_error - Retrieve the error number set by the last posix function that failed
- posix_getcwd - Pathname of current directory
- posix_getegid - Return the effective group ID of the current process
- posix_geteuid - Return the effective user ID of the current process
- posix_getgid - Return the real group ID of the current process
- posix_getgrgid - Return info about a group by group id
- posix_getgrnam - Return info about a group by name
- posix_getgroups - Return the group set of the current process
- posix_getlogin - Return login name
- posix_getpgid - Get process group id for job control
- posix_getpgrp - Return the current process group identifier
- posix_getpid - Return the current process identifier
- posix_getppid - Return the parent process identifier
- posix_getpwnam - Return info about a user by username
- posix_getpwuid - Return info about a user by user id
- posix_getrlimit - Return info about system resource limits
- posix_getsid - Get the current sid of the process
- posix_getuid - Return the real user ID of the current process
- posix_initgroups - Calculate the group access list
- posix_isatty - Determine if a file descriptor is an interactive terminal
- posix_kill - Send a signal to a process
- posix_mkfifo - Create a fifo special file (a named pipe)
- posix_mknod - Create a special or ordinary file (POSIX.1)
- posix_setegid - Set the effective GID of the current process
- posix_seteuid - Set the effective UID of the current process
- posix_setgid - Set the GID of the current process
- posix_setpgid - Set process group id for job control
- posix_setrlimit - Set system resource limits
- posix_setsid - Make the current process a session leader
- posix_setuid - Set the UID of the current process
- posix_strerror - Retrieve the system error message associated with the given errno
- posix_times - Get process times
- posix_ttyname - Determine terminal device name
- posix_uname - Get system name