Previous  Up  Next

Module Unix

module Unix: sig .. end
File descriptor.
module File_descr: sig .. end
File descriptor.

Error report

type error = Unix.error =
| E2BIG (*Argument list too long*)
| EACCES (*Permission denied*)
| EAGAIN (*Resource temporarily unavailable; try again*)
| EBADF (*Bad file descriptor*)
| EBUSY (*Resource unavailable*)
| ECHILD (*No child process*)
| EDEADLK (*Resource deadlock would occur*)
| EDOM (*Domain error for math functions, etc.*)
| EEXIST (*File exists*)
| EFAULT (*Bad address*)
| EFBIG (*File too large*)
| EINTR (*Function interrupted by signal*)
| EINVAL (*Invalid argument*)
| EIO (*Hardware I/O error*)
| EISDIR (*Is a directory*)
| EMFILE (*Too many open files by the process*)
| EMLINK (*Too many links*)
| ENAMETOOLONG (*Filename too long*)
| ENFILE (*Too many open files in the system*)
| ENODEV (*No such device*)
| ENOENT (*No such file or directory*)
| ENOEXEC (*Not an executable file*)
| ENOLCK (*No locks available*)
| ENOMEM (*Not enough memory*)
| ENOSPC (*No space left on device*)
| ENOSYS (*Function not supported*)
| ENOTDIR (*Not a directory*)
| ENOTEMPTY (*Directory not empty*)
| ENOTTY (*Inappropriate I/O control operation*)
| ENXIO (*No such device or address*)
| EPERM (*Operation not permitted*)
| EPIPE (*Broken pipe*)
| ERANGE (*Result too large*)
| EROFS (*Read-only file system*)
| ESPIPE (*Invalid seek e.g. on a pipe*)
| ESRCH (*No such process*)
| EXDEV (*Invalid link*)
| EWOULDBLOCK (*Operation would block*)
| EINPROGRESS (*Operation now in progress*)
| EALREADY (*Operation already in progress*)
| ENOTSOCK (*Socket operation on non-socket*)
| EDESTADDRREQ (*Destination address required*)
| EMSGSIZE (*Message too long*)
| EPROTOTYPE (*Protocol wrong type for socket*)
| ENOPROTOOPT (*Protocol not available*)
| EPROTONOSUPPORT (*Protocol not supported*)
| ESOCKTNOSUPPORT (*Socket type not supported*)
| EOPNOTSUPP (*Operation not supported on socket*)
| EPFNOSUPPORT (*Protocol family not supported*)
| EAFNOSUPPORT (*Address family not supported by protocol family*)
| EADDRINUSE (*Address already in use*)
| EADDRNOTAVAIL (*Can't assign requested address*)
| ENETDOWN (*Network is down*)
| ENETUNREACH (*Network is unreachable*)
| ENETRESET (*Network dropped connection on reset*)
| ECONNABORTED (*Software caused connection abort*)
| ECONNRESET (*Connection reset by peer*)
| ENOBUFS (*No buffer space available*)
| EISCONN (*Socket is already connected*)
| ENOTCONN (*Socket is not connected*)
| ESHUTDOWN (*Can't send after socket shutdown*)
| ETOOMANYREFS (*Too many references: can't splice*)
| ETIMEDOUT (*Connection timed out*)
| ECONNREFUSED (*Connection refused*)
| EHOSTDOWN (*Host is down*)
| EHOSTUNREACH (*No route to host*)
| ELOOP (*Too many levels of symbolic links*)
| EOVERFLOW (*File size or position not representable*)
| EUNKNOWNERR of int
The type of error codes. Errors defined in the POSIX standard and additional errors, mostly BSD. All other errors are mapped to EUNKNOWNERR.
val sexp_of_error : error -> Sexplib.Sexp.t
val error_of_sexp : Sexplib.Sexp.t -> error
Unknown error
exception Unix_error of error * string * string
Raised by the system calls below when an error is encountered. The first component is the error code; the second component is the function name; the third component is the string parameter to the function, if it has one, or the empty string otherwise.
val unix_error : int -> string -> string -> 'a
Raises Unix_error with a given errno, function name and argument
val error_message : error -> string
Return a string describing the given error code.
val handle_unix_error : (unit -> 'a) -> 'a
handle_unix_error f runs f () and returns the result. If the exception Unix_error is raised, it prints a message describing the error and exits with code 2.
val retry_until_no_eintr : (unit -> 'a) -> 'a
retry_until_no_eintr f returns f () unless f () fails with EINTR; in which case f () is run again until it raises a different error or returns a value.

Access to the process environment

val environment : unit -> string array
Return the process environment, as an array of strings with the format ``variable=value''.
val putenv : key:string -> data:string -> unit
Unix.putenv ~key ~data sets the value associated to a variable in the process environment. key is the name of the environment variable, and data its new associated value.
val unsetenv : string -> unit
unsetenv name deletes the variable name from the environment.

EINVAL name contained an ’=’ or an '\000' character.


Process handling

module Exit: sig .. end
The termination status of a process. 
module Exit_or_signal: sig .. end
module Exit_or_signal_or_stop: sig .. end
val exec : prog:string ->
       args:string list ->
       ?use_path:bool -> ?env:string list -> unit -> Common.never_returns
exec ~prog ~args ?search_path ?env execs prog with args. If use_path = true (the default) and prog doesn't contain a slash, then exec searches the PATH environment variable for prog. If env is supplied, it is used as the environment when prog is executed.
val fork_exec : prog:string ->
       args:string list -> ?use_path:bool -> ?env:string list -> unit -> Pid.t
fork_exec ~prog ~args ?use_path ?env () forks and execs prog with args in the child process, returning the child pid to the parent.
val execv : prog:string -> args:string array -> 'a
execv prog args execute the program in file prog, with the arguments args, and the current process environment. These execv* functions never return: on success, the current program is replaced by the new one; on failure, a UnixLabels.Unix_error exception is raised.
val execve : prog:string -> args:string array -> env:string array -> 'a
Same as UnixLabels.execv, except that the third argument provides the environment to the program executed.
val execvp : prog:string -> args:string array -> 'a
Same as UnixLabels.execv respectively, except that the program is searched in the path.
val execvpe : prog:string -> args:string array -> env:string array -> 'a
Same as UnixLabels.execve respectively, except that the program is searched in the path.
val fork : unit -> [ `In_the_child | `In_the_parent of Pid.t ]
fork () forks a new process. The return value indicates whether we are continuing in the child or the parent, and if the parent, includes the child's process id.

wait{,_nohang,_untraced,_nohang_untraced} ?restart wait_on is a family of functions that wait on a process to exit (normally or via a signal) or be stopped by a signal (if untraced is used). The wait_on argument specifies which processes to wait on. The nohang variants return None immediately if no such process exists. If nohang is not used, waitpid will block until one of the desired processes exits.

The non-nohang variants have a restart flag with (default true) that causes the system call to be retried upon EAGAIN|EINTR. The nohang variants do not have this flag because they don't block.

type wait_on = [ `Any | `Group of Pid.t | `My_group | `Pid of Pid.t ] 
val sexp_of_wait_on : wait_on -> Sexplib.Sexp.t
val wait_on_of_sexp : Sexplib.Sexp.t -> wait_on
val wait_on_of_sexp__ : Sexplib.Sexp.t -> wait_on
val wait : ?restart:bool -> wait_on -> Pid.t * Exit_or_signal.t
val wait_nohang : wait_on -> (Pid.t * Exit_or_signal.t) option
val wait_untraced : ?restart:bool ->
       wait_on -> Pid.t * Exit_or_signal_or_stop.t
val wait_nohang_untraced : wait_on -> (Pid.t * Exit_or_signal_or_stop.t) option
val system : string -> Exit_or_signal.t
Execute the given command, wait until it terminates, and return its termination status. The string is interpreted by the shell /bin/sh and therefore can contain redirections, quotes, variables, etc. The result WEXITED 127 indicates that the shell couldn't be executed.
val getpid : unit -> Pid.t
Return the pid of the process.
val getppid : unit -> Pid.t option
Return the pid of the parent process.
val getppid_exn : unit -> Pid.t
Return the pid of the parent process, if you're really sure you're never going to be the init process.
val nice : int -> int
Change the process priority. The integer argument is added to the ``nice'' value. (Higher values of the ``nice'' value mean lower priorities.) Return the new nice value.

Basic file input/output


The abstract type of file descriptors.
val stdin : File_descr.t
File descriptor for standard input.
val stdout : File_descr.t
File descriptor for standard output.
val stderr : File_descr.t
File descriptor for standard standard error.
type open_flag = Unix.open_flag =
| O_RDONLY (*Open for reading*)
| O_WRONLY (*Open for writing*)
| O_RDWR (*Open for reading and writing*)
| O_NONBLOCK (*Open in non-blocking mode*)
| O_APPEND (*Open for append*)
| O_CREAT (*Create if nonexistent*)
| O_TRUNC (*Truncate to 0 length if existing*)
| O_EXCL (*Fail if existing*)
| O_NOCTTY (*Don't make this dev a controlling tty*)
| O_DSYNC (*Writes complete as `Synchronised I/O data integrity completion'*)
| O_SYNC (*Writes complete as `Synchronised I/O file integrity completion'*)
| O_RSYNC (*Reads complete as writes (depending on O_SYNC/O_DSYNC)*)
| O_SHARE_DELETE
The flags to UnixLabels.openfile.
val sexp_of_open_flag : open_flag -> Sexplib.Sexp.t
val open_flag_of_sexp : Sexplib.Sexp.t -> open_flag
Windows only: allow the file to be deleted while still open

The flags to UnixLabels.openfile.

Open for reading

Open for writing

Open for reading and writing

Open in non-blocking mode

Open for append

Create if nonexistent

Truncate to 0 length if existing

Fail if existing

Don't make this dev a controlling tty

Writes complete as `Synchronised I/O data integrity completion'

Writes complete as `Synchronised I/O file integrity completion'

Reads complete as writes (depending on O_SYNC/O_DSYNC)
type file_perm = int
The type of file access rights.
val sexp_of_file_perm : file_perm -> Sexplib.Sexp.t
val file_perm_of_sexp : Sexplib.Sexp.t -> file_perm
val openfile : ?perm:file_perm ->
       mode:open_flag list -> string -> File_descr.t
Open the named file with the given flags. Third argument is the permissions to give to the file if it is created. Return a file descriptor on the named file. Default permissions 0o644.
val close : ?restart:bool -> File_descr.t -> unit
Close a file descriptor.
val with_file : ?perm:file_perm ->
       string ->
       mode:open_flag list -> f:(File_descr.t -> 'a) -> 'a
with_file file ~mode ~perm ~f opens file, and applies f to the resulting file descriptor. When f finishes (or raises), with_file closes the descriptor and returns the result of f (or raises).
val read : ?restart:bool ->
       ?pos:int -> ?len:int -> File_descr.t -> buf:string -> int
read fd buff ofs len reads len characters from descriptor fd, storing them in string buff, starting at position ofs in string buff. Return the number of characters actually read.
val write : ?pos:int -> ?len:int -> File_descr.t -> buf:string -> int
write fd buff ofs len writes len characters to descriptor fd, taking them from string buff, starting at position ofs in string buff. Return the number of characters actually written.

When an error is reported some characters might have already been written. Use single_write instead to ensure that this is not the case.

WARNING: write is an interruptible call and has no way to handle EINTR properly. You should most probably be using single write.

val single_write : ?restart:bool ->
       ?pos:int -> ?len:int -> File_descr.t -> buf:string -> int
Same as write but ensures that all errors are reported and that no character has ever been written when an error is reported.

Interfacing with the standard input/output library

val in_channel_of_descr : File_descr.t -> In_channel.t
Create an input channel reading from the given descriptor. The channel is initially in binary mode; use set_binary_mode_in ic false if text mode is desired.
val out_channel_of_descr : File_descr.t -> Out_channel.t
Create an output channel writing on the given descriptor. The channel is initially in binary mode; use set_binary_mode_out oc false if text mode is desired.
val descr_of_in_channel : In_channel.t -> File_descr.t
Return the descriptor corresponding to an input channel.
val descr_of_out_channel : Out_channel.t -> File_descr.t
Return the descriptor corresponding to an output channel.

Seeking and truncating

type seek_command = Unix.seek_command =
| SEEK_SET (*indicates positions relative to the beginning of the file*)
| SEEK_CUR (*indicates positions relative to the current position*)
| SEEK_END
POSITIONING modes for UnixLabels.lseek.
val sexp_of_seek_command : seek_command -> Sexplib.Sexp.t
val seek_command_of_sexp : Sexplib.Sexp.t -> seek_command
indicates positions relative to the end of the file
val lseek : File_descr.t -> int64 -> mode:seek_command -> int64
Set the current position for a file descriptor
val truncate : string -> len:int64 -> unit
Truncates the named file to the given size.
val ftruncate : File_descr.t -> len:int64 -> unit
Truncates the file corresponding to the given descriptor to the given size.

File statistics

type file_kind = Unix.file_kind =
| S_REG (*Regular file*)
| S_DIR (*Directory*)
| S_CHR (*Character device*)
| S_BLK (*Block device*)
| S_LNK (*Symbolic link*)
| S_FIFO (*Named pipe*)
| S_SOCK 
val sexp_of_file_kind : file_kind -> Sexplib.Sexp.t
val file_kind_of_sexp : Sexplib.Sexp.t -> file_kind
Socket
type stats = Unix.LargeFile.stats = {
   st_dev :int; (*Device number*)
   st_ino :int; (*Inode number*)
   st_kind :file_kind; (*Kind of the file*)
   st_perm :file_perm; (*Access rights*)
   st_nlink :int; (*Number of links*)
   st_uid :int; (*User id of the owner*)
   st_gid :int; (*Group ID of the file's group*)
   st_rdev :int; (*Device minor number*)
   st_size :int64; (*Size in bytes*)
   st_atime :float; (*Last access time*)
   st_mtime :float; (*Last modification time*)
   st_ctime :float; (*Last status change time*)
}
The informations returned by the UnixLabels.stat calls.
val sexp_of_stats : stats -> Sexplib.Sexp.t
val stats_of_sexp : Sexplib.Sexp.t -> stats
val stat : string -> stats
Return the information for the named file.
val lstat : string -> stats
Same as UnixLabels.stat, but in case the file is a symbolic link, return the information for the link itself.
val fstat : File_descr.t -> stats
Return the information for the file associated with the given descriptor.
module Native_file: sig .. end

Locking

type lock_command = Unix.lock_command =
| F_ULOCK (*Unlock a region*)
| F_LOCK (*Lock a region for writing, and block if already locked*)
| F_TLOCK (*Lock a region for writing, or fail if already locked*)
| F_TEST (*Test a region for other process locks*)
| F_RLOCK (*Lock a region for reading, and block if already locked*)
| F_TRLOCK
Commands for Unix.lockf.
val sexp_of_lock_command : lock_command -> Sexplib.Sexp.t
val lock_command_of_sexp : Sexplib.Sexp.t -> lock_command
Lock a region for reading, or fail if already locked
val lockf : File_descr.t ->
       mode:lock_command -> len:Int64.t -> unit
lockf fd cmd size place a lock on a file_descr that prevents any other process from calling lockf successfully on the same file. Due to a limitation in the current implementation the length will be converted to a native int, potentially throwing an exception if it is too large.
module Flock_command: sig .. end
val flock : File_descr.t -> Flock_command.t -> bool
flock fd cmd places or releases a lock on the fd as per the flock C call of the same name.
val isatty : File_descr.t -> bool
Return true if the given file descriptor refers to a terminal or console window, false otherwise.

Operations on file names

val unlink : string -> unit
Removes the named file
val rename : src:string -> dst:string -> unit
rename old new changes the name of a file from old to new.
val link : ?force:bool -> target:string -> link_name:string -> unit -> unit
link ?force ~target ~link_name () creates a hard link named link_name to the file named target. If force is true, an existing entry in place of link_name will be unlinked. This unlinking may raise a Unix error, e.g. if the entry is a directory.
force : default = false

File permissions and ownership

val chmod : string -> perm:file_perm -> unit
Change the permissions of the named file.
val fchmod : File_descr.t -> perm:file_perm -> unit
Change the permissions of an opened file.
val chown : string -> uid:int -> gid:int -> unit
Change the owner uid and owner gid of the named file.
val fchown : File_descr.t -> uid:int -> gid:int -> unit
Change the owner uid and owner gid of an opened file.
val umask : int -> int
Set the process creation mask, and return the previous mask.
val access : string -> [ `Exec | `Exists | `Read | `Write ] list -> (unit, exn) Result.t
Check that the process has the given permissions over the named file.
val access_exn : string -> [ `Exec | `Exists | `Read | `Write ] list -> unit

Operations on file descriptors

val dup : File_descr.t -> File_descr.t
Return a new file descriptor referencing the same file as the given descriptor.
val dup2 : src:File_descr.t -> dst:File_descr.t -> unit
dup2 fd1 fd2 duplicates fd1 to fd2, closing fd2 if already opened.
val set_nonblock : File_descr.t -> unit
Set the ``non-blocking'' flag on the given descriptor. When the non-blocking flag is set, reading on a descriptor on which there is temporarily no data available raises the EAGAIN or EWOULDBLOCK error instead of blocking; writing on a descriptor on which there is temporarily no room for writing also raises EAGAIN or EWOULDBLOCK.
val clear_nonblock : File_descr.t -> unit
Clear the ``non-blocking'' flag on the given descriptor. See UnixLabels.set_nonblock.
val set_close_on_exec : File_descr.t -> unit
Set the ``close-on-exec'' flag on the given descriptor. A descriptor with the close-on-exec flag is automatically closed when the current process starts another program with one of the exec functions.
val clear_close_on_exec : File_descr.t -> unit
Clear the ``close-on-exec'' flag on the given descriptor. See UnixLabels.set_close_on_exec.

Directories

val mkdir : ?perm:file_perm -> string -> unit
Create a directory. The permissions of the created directory are (perm & ~umask & 0777). The default perm is 0777.
val mkdir_p : ?perm:file_perm -> string -> unit
Create a directory recursively. The permissions of the created directory are those granted by mkdir ~perm.
val rmdir : string -> unit
Remove an empty directory.
val chdir : string -> unit
Change the process working directory.
val getcwd : unit -> string
Return the name of the current working directory.
val chroot : string -> unit
Change the process root directory.
type dir_handle = Unix.dir_handle
The type of descriptors over opened directories.
val opendir : ?restart:bool -> string -> dir_handle
Open a descriptor on a directory
val readdir : dir_handle -> string
Return the next entry in a directory.
Raises End_of_file when the end of the directory has been reached.
val rewinddir : dir_handle -> unit
Reposition the descriptor to the beginning of the directory
val closedir : dir_handle -> unit
Close a directory descriptor.
val fold_dir : init:'acc -> f:('acc -> string -> 'acc) -> string -> 'acc
val ls_dir : string -> string list

Pipes and redirections

val pipe : unit -> File_descr.t * File_descr.t
Create a pipe. The first component of the result is opened for reading, that's the exit to the pipe. The second component is opened for writing, that's the entrance to the pipe.
val mkfifo : string -> perm:file_perm -> unit
Create a named pipe with the given permissions.

High-level process and redirection management

module Process_info: sig .. end

Low-level process
val create_process : prog:string -> args:string list -> Process_info.t
create_process ~prog ~args forks a new process that executes the program prog with arguments args. The function returns the pid of the process along with file descriptors attached to stdin, stdout, and stderr of the new process. The executable file prog is searched for in the path. The new process has the same environment as the current process. Unlike in execve the program name is automatically passed as the first argument.
val create_process_env : ?working_dir:string ->
       prog:string ->
       args:string list ->
       env:[ `Extend of (string * string) list | `Replace of (string * string) list ] ->
       unit -> Process_info.t
create_process_env ~prog ~args ~env as create process, but takes an additional parameter that extends, or replaces the current environment. No effort is made to ensure that the keys passed in as env are unique, so if an environment variable is set twice the second version will override the first.
val open_process_in : string -> Pervasives.in_channel
High-level pipe and process management. These functions (with UnixLabels.open_process_out and UnixLabels.open_process) run the given command in parallel with the program, and return channels connected to the standard input and/or the standard output of the command. The command is interpreted by the shell /bin/sh (cf. system). Warning: writes on channels are buffered, hence be careful to call Pervasives.flush at the right times to ensure correct synchronization.
val open_process_out : string -> Pervasives.out_channel
See UnixLabels.open_process_in.
val open_process : string -> Pervasives.in_channel * Pervasives.out_channel
See UnixLabels.open_process_in.
module Process_channels: sig .. end
Similar to UnixLabels.open_process, but the second argument specifies the environment passed to the command. 
val open_process_full : string -> env:string array -> Process_channels.t
val close_process_in : Pervasives.in_channel -> Exit_or_signal.t
Close channels opened by UnixLabels.open_process_in, wait for the associated command to terminate, and return its termination status.
val close_process_out : Pervasives.out_channel -> Exit_or_signal.t
Close channels opened by UnixLabels.open_process_out, wait for the associated command to terminate, and return its termination status.
val close_process : Pervasives.in_channel * Pervasives.out_channel -> Exit_or_signal.t
Close channels opened by UnixLabels.open_process, wait for the associated command to terminate, and return its termination status.
val close_process_full : Process_channels.t -> Exit_or_signal.t
Close channels opened by UnixLabels.open_process_full, wait for the associated command to terminate, and return its termination status.

Symbolic links

val symlink : src:string -> dst:string -> unit
symlink source dest creates the file dest as a symbolic link to the file source.
val readlink : string -> string
Read the contents of a link.

Polling

module Select_fds: sig .. end
Wait until some input/output operations become possible on some channels. 
val select : ?restart:bool ->
       read:File_descr.t list ->
       write:File_descr.t list ->
       except:File_descr.t list ->
       timeout:float -> unit -> Select_fds.t
Setting restart to true means that we want select to restart automatically on EINTR (instead of propagating the exception)...
val pause : unit -> unit
Wait until a non-ignored, non-blocked signal is delivered.

Time functions

type process_times = Unix.process_times = {
   tms_utime :float; (*User time for the process*)
   tms_stime :float; (*System time for the process*)
   tms_cutime :float; (*User time for the children processes*)
   tms_cstime :float; (*System time for the children processes*)
}
The execution times (CPU times) of a process.
val sexp_of_process_times : process_times -> Sexplib.Sexp.t
val process_times_of_sexp : Sexplib.Sexp.t -> process_times
type tm = Unix.tm = {
   tm_sec :int; (*Seconds 0..59*)
   tm_min :int; (*Minutes 0..59*)
   tm_hour :int; (*Hours 0..23*)
   tm_mday :int; (*Day of month 1..31*)
   tm_mon :int; (*Month of year 0..11*)
   tm_year :int; (*Year - 1900*)
   tm_wday :int; (*Day of week (Sunday is 0)*)
   tm_yday :int; (*Day of year 0..365*)
   tm_isdst :bool; (*Daylight time savings in effect*)
}
The type representing wallclock time and calendar date.
val sexp_of_tm : tm -> Sexplib.Sexp.t
val tm_of_sexp : Sexplib.Sexp.t -> tm
val time : unit -> float
Return the current time since 00:00:00 GMT, Jan. 1, 1970, in seconds.
val gettimeofday : unit -> float
Same as Unix.time above, but with resolution better than 1 second.
val gmtime : float -> tm
Convert a time in seconds, as returned by UnixLabels.time, into a date and a time. Assumes UTC.
val timegm : tm -> float
Convert a UTC time in a tm record to a time in seconds
val localtime : float -> tm
Convert a time in seconds, as returned by UnixLabels.time, into a date and a time. Assumes the local time zone.
val mktime : tm -> float * tm
Convert a date and time, specified by the tm argument, into a time in seconds, as returned by UnixLabels.time. Also return a normalized copy of the given tm record, with the tm_wday, tm_yday, and tm_isdst fields recomputed from the other fields. The tm argument is interpreted in the local time zone.
val strftime : tm -> string -> string
Convert a date and time, specified by the tm argument, into a formatted string. See 'man strftime' for format options.
val alarm : int -> int
Schedule a SIGALRM signal after the given number of seconds.
val sleep : int -> unit
Stop execution for the given number of seconds.
val nanosleep : float -> float
nanosleep f delays execution of the program for at least f seconds. The function can return earlier if a signal has been delivered, in which case the number of seconds left is returned. Any other failure raises an exception.
val times : unit -> process_times
Return the execution times of the process.
val utimes : string -> access:float -> modif:float -> unit
Set the last access time (second arg) and last modification time (third arg) for a file. Times are expressed in seconds from 00:00:00 GMT, Jan. 1, 1970.
type interval_timer = Unix.interval_timer =
| ITIMER_REAL (*decrements in real time, and sends the signal SIGALRM when expired.*)
| ITIMER_VIRTUAL (*decrements in process virtual time, and sends SIGVTALRM when expired.*)
| ITIMER_PROF
The three kinds of interval timers.
val sexp_of_interval_timer : interval_timer -> Sexplib.Sexp.t
val interval_timer_of_sexp : Sexplib.Sexp.t -> interval_timer
(for profiling) decrements both when the process is running and when the system is running on behalf of the process; it sends SIGPROF when expired.
type interval_timer_status = Unix.interval_timer_status = {
   it_interval :float; (*Period*)
   it_value :float; (*Current value of the timer*)
}
The type describing the status of an interval timer
val sexp_of_interval_timer_status : interval_timer_status -> Sexplib.Sexp.t
val interval_timer_status_of_sexp : Sexplib.Sexp.t -> interval_timer_status
val getitimer : interval_timer -> interval_timer_status
Return the current status of the given interval timer.
val setitimer : interval_timer ->
       interval_timer_status -> interval_timer_status
setitimer t s sets the interval timer t and returns its previous status. The s argument is interpreted as follows: s.it_value, if nonzero, is the time to the next timer expiration; s.it_interval, if nonzero, specifies a value to be used in reloading it_value when the timer expires. Setting s.it_value to zero disable the timer. Setting s.it_interval to zero causes the timer to be disabled after its next expiration.

User id, group id
 It's highly recommended to read the straight unix docs on these functions for more color. You can get that info from man pages or http://www.opengroup.org/onlinepubs/000095399/functions/setuid.html
val getuid : unit -> int
Return the user id of the user executing the process.
val geteuid : unit -> int
Return the effective user id under which the process runs.
val setuid : int -> unit
Sets the real user id and effective user id for the process. Only use this when superuser. To setuid as an ordinary user, see Core_extended.Unix.seteuid.
val getgid : unit -> int
Return the group id of the user executing the process.
val getegid : unit -> int
Return the effective group id under which the process runs.
val setgid : int -> unit
Set the real group id and effective group id for the process.
val getgroups : unit -> int array
Return the list of groups to which the user executing the process belongs.
module Passwd: sig .. end
Structure of entries in the passwd database 
module Group: sig .. end
Structure of entries in the groups database. 
val getlogin : unit -> string
Return the login name of the user executing the process.
module Protocol_family: sig .. end

Internet addresses

module Inet_addr: sig .. end

Sockets

type socket_domain = Unix.socket_domain =
| PF_UNIX (*Unix domain*)
| PF_INET (*Internet domain*)
| PF_INET6
The type of socket domains.
val bin_size_socket_domain : socket_domain Bin_prot.Size.sizer
val bin_write_socket_domain : socket_domain Bin_prot.Write_ml.writer
val bin_write_socket_domain_ : socket_domain Bin_prot.Unsafe_write_c.writer
val bin_writer_socket_domain : socket_domain Bin_prot.Type_class.writer
val bin_read_socket_domain : socket_domain Bin_prot.Read_ml.reader
val bin_read_socket_domain_ : socket_domain Bin_prot.Unsafe_read_c.reader
val bin_read_socket_domain__ : (int -> socket_domain) Bin_prot.Unsafe_read_c.reader
val bin_reader_socket_domain : socket_domain Bin_prot.Type_class.reader
val bin_socket_domain : socket_domain Bin_prot.Type_class.t
val sexp_of_socket_domain : socket_domain -> Sexplib.Sexp.t
val socket_domain_of_sexp : Sexplib.Sexp.t -> socket_domain
type socket_type = Unix.socket_type =
| SOCK_STREAM (*Stream socket*)
| SOCK_DGRAM (*Datagram socket*)
| SOCK_RAW (*Raw socket*)
| SOCK_SEQPACKET
The type of socket kinds, specifying the semantics of communications.
val bin_size_socket_type : socket_type Bin_prot.Size.sizer
val bin_write_socket_type : socket_type Bin_prot.Write_ml.writer
val bin_write_socket_type_ : socket_type Bin_prot.Unsafe_write_c.writer
val bin_writer_socket_type : socket_type Bin_prot.Type_class.writer
val bin_read_socket_type : socket_type Bin_prot.Read_ml.reader
val bin_read_socket_type_ : socket_type Bin_prot.Unsafe_read_c.reader
val bin_read_socket_type__ : (int -> socket_type) Bin_prot.Unsafe_read_c.reader
val bin_reader_socket_type : socket_type Bin_prot.Type_class.reader
val bin_socket_type : socket_type Bin_prot.Type_class.t
val sexp_of_socket_type : socket_type -> Sexplib.Sexp.t
val socket_type_of_sexp : Sexplib.Sexp.t -> socket_type
type sockaddr = Unix.sockaddr =
| ADDR_UNIX of string
| ADDR_INET of Inet_addr.t * int
The type of socket addresses. ADDR_UNIX name is a socket address in the Unix domain; name is a file name in the file system. ADDR_INET(addr,port) is a socket address in the Internet domain; addr is the Internet address of the machine, and port is the port number.
val bin_size_sockaddr : sockaddr Bin_prot.Size.sizer
val bin_write_sockaddr : sockaddr Bin_prot.Write_ml.writer
val bin_write_sockaddr_ : sockaddr Bin_prot.Unsafe_write_c.writer
val bin_writer_sockaddr : sockaddr Bin_prot.Type_class.writer
val bin_read_sockaddr : sockaddr Bin_prot.Read_ml.reader
val bin_read_sockaddr_ : sockaddr Bin_prot.Unsafe_read_c.reader
val bin_read_sockaddr__ : (int -> sockaddr) Bin_prot.Unsafe_read_c.reader
val bin_reader_sockaddr : sockaddr Bin_prot.Type_class.reader
val bin_sockaddr : sockaddr Bin_prot.Type_class.t
val sexp_of_sockaddr : sockaddr -> Sexplib.Sexp.t
val sockaddr_of_sexp : Sexplib.Sexp.t -> sockaddr
val domain_of_sockaddr : sockaddr -> socket_domain
Return the socket domain adequate for the given socket address.
val socket : domain:socket_domain ->
       kind:socket_type -> protocol:int -> File_descr.t
Create a new socket in the given domain, and with the given kind. The third argument is the protocol type; 0 selects the default protocol for that kind of sockets.
val socketpair : domain:socket_domain ->
       kind:socket_type ->
       protocol:int -> File_descr.t * File_descr.t
Create a pair of unnamed sockets, connected together.
val accept : File_descr.t -> File_descr.t * sockaddr
Accept connections on the given socket. The returned descriptor is a socket connected to the client; the returned address is the address of the connecting client.
val bind : File_descr.t -> addr:sockaddr -> unit
Bind a socket to an address.
val connect : File_descr.t -> addr:sockaddr -> unit
Connect a socket to an address.
val listen : File_descr.t -> max:int -> unit
Set up a socket for receiving connection requests. The integer argument is the maximal number of pending requests.
type shutdown_command = Unix.shutdown_command =
| SHUTDOWN_RECEIVE (*Close for receiving*)
| SHUTDOWN_SEND (*Close for sending*)
| SHUTDOWN_ALL
The type of commands for shutdown.
val sexp_of_shutdown_command : shutdown_command -> Sexplib.Sexp.t
val shutdown_command_of_sexp : Sexplib.Sexp.t -> shutdown_command
Close both
val shutdown : File_descr.t -> mode:shutdown_command -> unit
Shutdown a socket connection. SHUTDOWN_SEND as second argument causes reads on the other end of the connection to return an end-of-file condition. SHUTDOWN_RECEIVE causes writes on the other end of the connection to return a closed pipe condition (SIGPIPE signal).
val getsockname : File_descr.t -> sockaddr
Return the address of the given socket.
val getpeername : File_descr.t -> sockaddr
Return the address of the host connected to the given socket.
type msg_flag = Unix.msg_flag =
| MSG_OOB
| MSG_DONTROUTE
| MSG_PEEK
The flags for UnixLabels.recv, UnixLabels.recvfrom, UnixLabels.send and UnixLabels.sendto.
val sexp_of_msg_flag : msg_flag -> Sexplib.Sexp.t
val msg_flag_of_sexp : Sexplib.Sexp.t -> msg_flag
val recv : File_descr.t ->
       buf:string -> pos:int -> len:int -> mode:msg_flag list -> int
Receive data from an unconnected socket.
val recvfrom : File_descr.t ->
       buf:string ->
       pos:int ->
       len:int -> mode:msg_flag list -> int * sockaddr
Receive data from an unconnected socket.
val send : File_descr.t ->
       buf:string -> pos:int -> len:int -> mode:msg_flag list -> int
Send data over an unconnected socket.
val sendto : File_descr.t ->
       buf:string ->
       pos:int ->
       len:int -> mode:msg_flag list -> addr:sockaddr -> int
Send data over an unconnected socket.

Socket options

type socket_bool_option =
| SO_DEBUG (*Record debugging information*)
| SO_BROADCAST (*Permit sending of broadcast messages*)
| SO_REUSEADDR (*Allow reuse of local addresses for bind*)
| SO_KEEPALIVE (*Keep connection active*)
| SO_DONTROUTE (*Bypass the standard routing algorithms*)
| SO_OOBINLINE (*Leave out-of-band data in line*)
| SO_ACCEPTCONN
| TCP_NODELAY (*Control the Nagle algorithm for TCP sockets*)
| IPV6_ONLY
The socket options that can be consulted with UnixLabels.getsockopt and modified with UnixLabels.setsockopt. These options have a boolean (true/false) value.
val sexp_of_socket_bool_option : socket_bool_option -> Sexplib.Sexp.t
val socket_bool_option_of_sexp : Sexplib.Sexp.t -> socket_bool_option
Forbid binding an IPv6 socket to an IPv4 address
type socket_int_option =
| SO_SNDBUF (*Size of send buffer*)
| SO_RCVBUF (*Size of received buffer*)
| SO_ERROR (*Report the error status and clear it*)
| SO_TYPE (*Report the socket type*)
| SO_RCVLOWAT (*Minimum number of bytes to process for input operations*)
| SO_SNDLOWAT
The socket options that can be consulted with UnixLabels.getsockopt_int and modified with UnixLabels.setsockopt_int. These options have an integer value.
val sexp_of_socket_int_option : socket_int_option -> Sexplib.Sexp.t
val socket_int_option_of_sexp : Sexplib.Sexp.t -> socket_int_option
type socket_optint_option =
| SO_LINGER (*Whether to linger on closed connections with sexp that have data present, and for how long (in seconds)*)
The socket options that can be consulted with UnixLabels.getsockopt_optint and modified with UnixLabels.setsockopt_optint. These options have a value of type int option, with None meaning ``disabled''.
type socket_float_option =
| SO_RCVTIMEO (*Timeout for input operations*)
| SO_SNDTIMEO
The socket options that can be consulted with UnixLabels.getsockopt_float and modified with UnixLabels.setsockopt_float. These options have a floating-point value representing a time in seconds. The value 0 means infinite timeout.
val sexp_of_socket_float_option : socket_float_option -> Sexplib.Sexp.t
val socket_float_option_of_sexp : Sexplib.Sexp.t -> socket_float_option
Timeout for output operations
val getsockopt : File_descr.t -> socket_bool_option -> bool
Return the current status of a boolean-valued option in the given socket.
val setsockopt : File_descr.t -> socket_bool_option -> bool -> unit
Set or clear a boolean-valued option in the given socket.
val getsockopt_int : File_descr.t -> socket_int_option -> int
Same as UnixLabels.getsockopt for an integer-valued socket option.
val setsockopt_int : File_descr.t -> socket_int_option -> int -> unit
Same as UnixLabels.setsockopt for an integer-valued socket option.
val getsockopt_optint : File_descr.t -> socket_optint_option -> int option
Same as UnixLabels.getsockopt for a socket option whose value is an int option.
val setsockopt_optint : File_descr.t ->
       socket_optint_option -> int option -> unit
Same as UnixLabels.setsockopt for a socket option whose value is an int option.
val getsockopt_float : File_descr.t -> socket_float_option -> float
Same as UnixLabels.getsockopt for a socket option whose value is a floating-point number.
val setsockopt_float : File_descr.t -> socket_float_option -> float -> unit
Same as UnixLabels.setsockopt for a socket option whose value is a floating-point number.

High-level network connection functions

val open_connection : sockaddr -> Pervasives.in_channel * Pervasives.out_channel
Connect to a server at the given address. Return a pair of buffered channels connected to the server. Remember to call Pervasives.flush on the output channel at the right times to ensure correct synchronization.
val shutdown_connection : Pervasives.in_channel -> unit
``Shut down'' a connection established with UnixLabels.open_connection; that is, transmit an end-of-file condition to the server reading on the other side of the connection.
val establish_server : (Pervasives.in_channel -> Pervasives.out_channel -> unit) ->
       addr:sockaddr -> unit
Establish a server on the given address. The function given as first argument is called for each connection with two buffered channels connected to the client. A new process is created for each connection. The function UnixLabels.establish_server never returns normally.

Host and protocol databases

val gethostname : unit -> string
Return the name of the local host.
module Host: sig .. end
module Protocol: sig .. end
module Service: sig .. end
type addr_info = {
   ai_family :socket_domain; (*Socket domain*)
   ai_socktype :socket_type; (*Socket type*)
   ai_protocol :int; (*Socket protocol number*)
   ai_addr :sockaddr; (*Address*)
   ai_canonname :string;
}
Address information returned by Unix.getaddrinfo.
val sexp_of_addr_info : addr_info -> Sexplib.Sexp.t
val addr_info_of_sexp : Sexplib.Sexp.t -> addr_info
type getaddrinfo_option =
| AI_FAMILY of socket_domain (*Impose the given socket domain*)
| AI_SOCKTYPE of socket_type (*Impose the given socket type*)
| AI_PROTOCOL of int (*Impose the given protocol*)
| AI_NUMERICHOST (*Do not call name resolver, expect numeric IP address*)
| AI_CANONNAME (*Fill the ai_canonname field of the result*)
| AI_PASSIVE
Options to Unix.getaddrinfo.
val sexp_of_getaddrinfo_option : getaddrinfo_option -> Sexplib.Sexp.t
val getaddrinfo_option_of_sexp : Sexplib.Sexp.t -> getaddrinfo_option
val getaddrinfo : string ->
       string -> getaddrinfo_option list -> addr_info list
getaddrinfo host service opts returns a list of Unix.addr_info records describing socket parameters and addresses suitable for communicating with the given host and service. The empty list is returned if the host or service names are unknown, or the constraints expressed in opts cannot be satisfied.

host is either a host name or the string representation of an IP address. host can be given as the empty string; in this case, the ``any'' address or the ``loopback'' address are used, depending whether opts contains AI_PASSIVE. service is either a service name or the string representation of a port number. service can be given as the empty string; in this case, the port field of the returned addresses is set to 0. opts is a possibly empty list of options that allows the caller to force a particular socket domain (e.g. IPv6 only, or IPv4 only) or a particular socket type (e.g. TCP only or UDP only).

type name_info = {
   ni_hostname :string; (*Name or IP address of host*)
   ni_service :string;
}
Host and service information returned by Unix.getnameinfo.
val sexp_of_name_info : name_info -> Sexplib.Sexp.t
val name_info_of_sexp : Sexplib.Sexp.t -> name_info
Name of service or port number
type getnameinfo_option =
| NI_NOFQDN (*Do not qualify local host names*)
| NI_NUMERICHOST (*Always return host as IP address*)
| NI_NAMEREQD (*Fail if host name cannot be determined*)
| NI_NUMERICSERV (*Always return service as port number*)
| NI_DGRAM
Options to Unix.getnameinfo.
val sexp_of_getnameinfo_option : getnameinfo_option -> Sexplib.Sexp.t
val getnameinfo_option_of_sexp : Sexplib.Sexp.t -> getnameinfo_option
val getnameinfo : sockaddr ->
       getnameinfo_option list -> name_info
getnameinfo addr opts returns the host name and service name corresponding to the socket address addr. opts is a possibly empty list of options that governs how these names are obtained. Raise Not_found if an error occurs.

Getting terminal size



Terminal interface


The following functions implement the POSIX standard terminal interface. They provide control over asynchronous communication ports and pseudo-terminals. Refer to the termios man page for a complete description.
module Terminal_io: sig .. end
val get_sockaddr : string -> int -> sockaddr
Get a sockaddr from a hostname or IP, and a port
val set_in_channel_timeout : Pervasives.in_channel -> float -> unit
Set a timeout for a socket associated with an in_channel
val set_out_channel_timeout : Pervasives.out_channel -> float -> unit
Set a timeout for a socket associated with an out_channel
val exit_immediately : int -> 'a
exit_immediately exit_code immediately calls the exit system call with the given exit code without performing any other actions (unlike Pervasives.exit). Does not return.

Filesystem functions


val mknod : ?file_kind:file_kind ->
       ?perm:int -> ?major:int -> ?minor:int -> string -> unit
mknod ?file_kind ?perm ?major ?minor path creates a filesystem entry. Note that only FIFO-entries are guaranteed to be supported across all platforms as required by the POSIX-standard. On Linux directories and symbolic links cannot be created with this function. Use Unix.mkdir and Unix.symlink instead there respectively.
Raises
file_kind : default = S_REG (= regular file)
perm : default = 0o600 (= read/write for user only)
major : default = 0
minor : default = 0

I/O vectors


module IOVec: sig .. end
I/O-vectors for scatter/gather-operations

I/O functions


val dirfd : dir_handle -> File_descr.t

Extract a file descriptor from a directory handle.
val sync : unit -> unit
Synchronize all filesystem buffers with disk.
val fsync : File_descr.t -> unit
val fdatasync : File_descr.t -> unit
Synchronize the kernel buffers of a given file descriptor with disk, but do not necessarily write file attributes.
val readdir_ino : dir_handle -> string * nativeint
readdir_ino dh return the next entry in a directory (((filename, inode)).
Raises End_of_file when the end of the directory has been reached.
val read_assume_fd_is_nonblocking : File_descr.t -> ?pos:int -> ?len:int -> string -> int
read_assume_fd_is_nonblocking fd ?pos ?len buf calls the system call read ASSUMING THAT IT IS NOT GOING TO BLOCK. Reads at most len bytes into buffer buf starting at position pos.
Raises Returns the number of bytes actually read.
pos : = 0
len : = String.length buf - pos
val write_assume_fd_is_nonblocking : File_descr.t -> ?pos:int -> ?len:int -> string -> int
write_assume_fd_is_nonblocking fd ?pos ?len buf calls the system call write ASSUMING THAT IT IS NOT GOING TO BLOCK. Writes at most len bytes from buffer buf starting at position pos.
Raises Returns the number of bytes actually written.
pos : = 0
len : = String.length buf - pos
val writev_assume_fd_is_nonblocking : File_descr.t -> ?count:int -> string IOVec.t array -> int
writev_assume_fd_is_nonblocking fd ?count iovecs calls the system call writev ASSUMING THAT IT IS NOT GOING TO BLOCK using count I/O-vectors iovecs.
Raises Returns the number of bytes actually written.
val writev : File_descr.t -> ?count:int -> string IOVec.t array -> int
writev fd ?count iovecs like Unix.writev_assume_fd_is_nonblocking, but does not require the descriptor to not block. If you feel you have to use this function, you should probably have chosen I/O-vectors that build on bigstrings, because this function has to internally blit the I/O-vectors (ordinary OCaml strings) to intermediate buffers on the C-heap.
Raises Returns the number of bytes actually written.
val pselect : File_descr.t list ->
       File_descr.t list ->
       File_descr.t list ->
       float ->
       int list ->
       File_descr.t list * File_descr.t list *
       File_descr.t list
pselect rfds wfds efds timeout sigmask like Unix.select but also allows one to wait for the arrival of signals.
module RLimit: sig .. end
Resource limits 
module Resource_usage: sig .. end
Resource usage -- For details, "man getrusage" 
type sysconf =
| ARG_MAX
| CHILD_MAX
| HOST_NAME_MAX
| LOGIN_NAME_MAX
| OPEN_MAX
| PAGESIZE
| RE_DUP_MAX
| STREAM_MAX
| SYMLOOP_MAX
| TTY_NAME_MAX
| TZNAME_MAX
| POSIX_VERSION
| PHYS_PAGES
| AVPHYS_PAGES
| IOV_MAX

System configuration


val sexp_of_sysconf : sysconf -> Sexplib.Sexp.t
val sysconf_of_sexp : Sexplib.Sexp.t -> sysconf
val sysconf : sysconf -> int64

Temporary file and directory creation


val mkstemp : string -> string * File_descr.t
mkstemp prefix creates and opens a unique temporary file with prefix, automatically appending a suffix of six random characters to make the name unique.
Raises Unix_error on errors.
val mkdtemp : string -> string
mkdtemp prefix creates a temporary directory with prefix, automatically appending a suffix of six random characters to make the name unique.
Raises Unix_error on errors. k

Signal handling


val abort : unit -> 'a

User id, group id


val initgroups : string -> int -> unit

Globbing and shell expansion


val fnmatch : ?flags:[ `Casefold
              | `File_name
              | `Leading_dir
              | `No_escape
              | `Pathname
              | `Period ] list ->
       pat:string -> string -> bool
val wordexp : ?flags:[ `No_cmd | `Show_err | `Undef ] list -> string -> string array

System information


module Utsname: sig .. end
val uname : unit -> Utsname.t

Additional IP functionality


val if_indextoname : int -> string
val mcast_join : ?ifname:string -> File_descr.t -> sockaddr -> unit
mcast_join ?ifname sock addr join a multicast group at addr with socket sock, optionally using network interface ifname.
ifname : default = any interface
val mcast_leave : ?ifname:string -> File_descr.t -> sockaddr -> unit
mcast_leave ?ifname sock addr leaves a multicast group at addr with socket sock, optionally using network interface ifname.
ifname : default = any interface
module Scheduler: sig .. end
module Priority: sig .. end
module Mman: sig .. end