Module(Unix)

NAME
Unix - Interface to the Unix system

Module
Module Unix

Documentation

Module Unix
 : sig end

Interface to the Unix system

=== Error report === type 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 (* Unknown error *)

The type of error codes. Errors defined in the POSIX standard and additional errors from UNIX98 and BSD. All other errors are mapped to EUNKNOWNERR.

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 error_message : error -> string

Return a string describing the given error code.

val handle_unix_error : ('a -> 'b) -> 'a -> 'b

handle_unix_error f x applies f to x and returns the result. If the exception Unix_error is raised, it prints a message describing the error and exits with code 2.

=== 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 getenv : string -> string

Return the value associated to a variable in the process environment. Raise Not_found if the variable is unbound. (This function is identical to Sys.getenv

val putenv : string -> string -> unit

Unix.putenv name value sets the value associated to a variable in the process environment. name is the name of the environment variable, and value its new associated value.

=== Process handling === type process_status =
 | WEXITED of int (* The process terminated normally by exit ; the argument is the return code. *)
 | WSIGNALED of int (* The process was killed by a signal; the argument is the signal number. *)
 | WSTOPPED of int (* The process was stopped by a signal; the argument is the signal number. *)

The termination status of a process.

type wait_flag =
 | WNOHANG (* do not block if no child has died yet, but immediately return with a pid equal to 0. *)
 | WUNTRACED (* report also the children that receive stop signals. *)

Flags for Unix.waitpid

val execv : string -> string array -> unit

execv prog args execute the program in file prog , with the arguments args , and the current process environment.

val execve : string -> string array -> string array -> unit

Same as Unix.execv , except that the third argument provides the environment to the program executed.

val execvp : string -> string array -> unit

Same as Unix.execv respectively, except that the program is searched in the path.

val execvpe : string -> string array -> string array -> unit

Same as Unix.execvp respectively, except that the program is searched in the path.

val fork : unit -> int

Fork a new process. The returned integer is 0 for the child process, the pid of the child process for the parent process.

val wait : unit -> int * process_status

Wait until one of the children processes die, and return its pid and termination status.

val waitpid : wait_flag list -> int -> int * process_status

Same as Unix.wait , but waits for the process whose pid is given. A pid of -1 means wait for any child. A pid of 0 means wait for any child in the same process group as the current process. Negative pid arguments represent process groups. The list of options indicates whether waitpid should return immediately without waiting, or also report stopped children.

val system : string -> process_status

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 -> int

Return the pid of the process.

val getppid : unit -> int

Return the pid of the parent 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 === type file_descr

The abstract type of file descriptors.

val stdin : file_descr

File descriptor for standard input.

val stdout : file_descr

File descriptor for standard output.

val stderr : file_descr

File descriptor for standard standard error.

type 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) *)

The flags to Unix.openfile

type file_perm = int

The type of file access rights.

val openfile : string -> open_flag list -> file_perm -> file_descr

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.

val close : file_descr -> unit

Close a file descriptor.

val read : file_descr -> string -> int -> int -> int

read fd buff ofs len reads len characters from descriptor fd , storing them in string buff , starting at position ofs in string buff

val write : file_descr -> string -> int -> int -> int

write fd buff ofs len writes len characters to descriptor fd , taking them from string buff , starting at position ofs in string buff written.

=== Interfacing with the standard input/output library === val in_channel_of_descr : file_descr -> Pervasives.in_channel

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 -> Pervasives.out_channel

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 : Pervasives.in_channel -> file_descr

Return the descriptor corresponding to an input channel.

val descr_of_out_channel : Pervasives.out_channel -> file_descr

Return the descriptor corresponding to an output channel.

=== Seeking and truncating === type seek_command =
 | SEEK_SET (* indicates positions relative to the beginning of the file *)
 | SEEK_CUR (* indicates positions relative to the current position *)
 | SEEK_END (* indicates positions relative to the end of the file *)

Positioning modes for Unix.lseek

val lseek : file_descr -> int -> seek_command -> int

Set the current position for a file descriptor

val truncate : string -> int -> unit

Truncates the named file to the given size.

val ftruncate : file_descr -> int -> unit

Truncates the file corresponding to the given descriptor to the given size.

=== File statistics === type 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 (* Socket *)

type 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 : int ; (* 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 Unix.stat calls.

val stat : string -> stats

Return the informations for the named file.

val lstat : string -> stats

Same as Unix.stat , but in case the file is a symbolic link, return the informations for the link itself.

val fstat : file_descr -> stats

Return the informations for the file associated with the given descriptor.

=== File operations on large files === module LargeFile : sig end

File operations on large files. This sub-module provides 64-bit variants of the functions Unix.lseek (for positioning a file descriptor), Unix.truncate and Unix.ftruncate (for changing the size of a file), and Unix.stat , Unix.lstat and Unix.fstat (for obtaining information on files). These alternate functions represent positions and sizes by 64-bit integers (type int64 ) instead of regular integers (type int ), thus allowing operating on files whose sizes are greater than max_int

=== Operations on file names === val unlink : string -> unit

Removes the named file

val rename : string -> string -> unit

rename old new changes the name of a file from old to new

val link : string -> string -> unit

link source dest creates a hard link named dest to the file named source

=== File permissions and ownership === type access_permission =
 | R_OK (* Read permission *)
 | W_OK (* Write permission *)
 | X_OK (* Execution permission *)
 | F_OK (* File exists *)

Flags for the Unix.access call.

val chmod : string -> file_perm -> unit

Change the permissions of the named file.

val fchmod : file_descr -> file_perm -> unit

Change the permissions of an opened file.

val chown : string -> int -> int -> unit

Change the owner uid and owner gid of the named file.

val fchown : file_descr -> int -> int -> unit

Change the owner uid and owner gid of an opened file.

val umask : int -> int

Set the process's file mode creation mask, and return the previous mask.

val access : string -> access_permission list -> unit

Check that the process has the given permissions over the named file. Raise Unix_error otherwise.

=== Operations on file descriptors === val dup : file_descr -> file_descr

Return a new file descriptor referencing the same file as the given descriptor.

val dup2 : file_descr -> file_descr -> unit

dup2 fd1 fd2 duplicates fd1 to fd2 , closing fd2 if already opened.

val set_nonblock : file_descr -> 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 -> unit

Clear the ``non-blocking'' flag on the given descriptor. See Unix.set_nonblock

val set_close_on_exec : file_descr -> 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 -> unit

Clear the ``close-on-exec'' flag on the given descriptor. See Unix.set_close_on_exec

=== Directories === val mkdir : string -> file_perm -> unit

Create a directory with the given permissions.

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

The type of descriptors over opened directories.

val opendir : 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.

=== Pipes and redirections === val pipe : unit -> file_descr * file_descr

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 -> file_perm -> unit

Create a named pipe with the given permissions.

=== High-level process and redirection management === val create_process : string -> string array -> file_descr -> file_descr -> file_descr -> int

create_process prog args new_stdin new_stdout new_stderr forks a new process that executes the program in file prog , with arguments args process is returned immediately; the new process executes concurrently with the current process. The standard input and outputs of the new process are connected to the descriptors new_stdin , new_stdout and new_stderr Passing e.g. stdout for new_stdout prevents the redirection and causes the new process to have the same standard output as the current process. The executable file prog is searched in the path. The new process has the same environment as the current process.

val create_process_env : string -> string array -> string array -> file_descr -> file_descr -> file_descr -> int

create_process_env prog args env new_stdin new_stdout new_stderr works as Unix.create_process , except that the extra argument env specifies the environment passed to the program.

val open_process_in : string -> Pervasives.in_channel

High-level pipe and process management. This function runs the given command in parallel with the program. The standard output of the command is redirected to a pipe, which can be read via the returned input channel. The command is interpreted by the shell /bin/sh (cf. system ).

val open_process_out : string -> Pervasives.out_channel

Same as Unix.open_process_in , but redirect the standard input of the command to a pipe. Data written to the returned output channel is sent to the standard input of the command. Warning: writes on output channels are buffered, hence be careful to call Pervasives.flush at the right times to ensure correct synchronization.

val open_process : string -> Pervasives.in_channel * Pervasives.out_channel

Same as Unix.open_process_out , but redirects both the standard input and standard output of the command to pipes connected to the two returned channels. The input channel is connected to the output of the command, and the output channel to the input of the command.

val open_process_full : string -> string array -> Pervasives.in_channel * Pervasives.out_channel * Pervasives.in_channel

Similar to Unix.open_process , but the second argument specifies the environment passed to the command. The result is a triple of channels connected respectively to the standard output, standard input, and standard error of the command.

val close_process_in : Pervasives.in_channel -> process_status

Close channels opened by Unix.open_process_in , wait for the associated command to terminate, and return its termination status.

val close_process_out : Pervasives.out_channel -> process_status

Close channels opened by Unix.open_process_out , wait for the associated command to terminate, and return its termination status.

val close_process : Pervasives.in_channel * Pervasives.out_channel -> process_status

Close channels opened by Unix.open_process , wait for the associated command to terminate, and return its termination status.

val close_process_full : Pervasives.in_channel * Pervasives.out_channel * Pervasives.in_channel -> process_status

Close channels opened by Unix.open_process_full , wait for the associated command to terminate, and return its termination status.

=== Symbolic links === val symlink : string -> 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 === val select : file_descr list -> file_descr list -> file_descr list -> float -> file_descr list * file_descr list * file_descr list

Wait until some input/output operations become possible on some channels. The three list arguments are, respectively, a set of descriptors to check for reading (first argument), for writing (second argument), or for exceptional conditions (third argument). The fourth argument is the maximal timeout, in seconds; a negative fourth argument means no timeout (unbounded wait). The result is composed of three sets of descriptors: those ready for reading (first component), ready for writing (second component), and over which an exceptional condition is pending (third component).

=== Locking === type 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 (* Lock a region for reading, or fail if already locked *)

Commands for Unix.lockf

val lockf : file_descr -> lock_command -> int -> unit

lockf fd cmd size puts a lock on a region of the file opened as fd fd (as set by Unix.lseek ), and extends size bytes forward if size is positive, size bytes backwards if size is negative, or to the end of the file if size is zero. A write lock (set with F_LOCK or F_TLOCK ) prevents any other process from acquiring a read or write lock on the region. A read lock (set with F_RLOCK or F_TRLOCK ) prevents any other process from acquiring a write lock on the region, but lets other processes acquire read locks on it.

=== Signals Note: installation of signal handlers is performed via the functions Sys.signal and Sys.set_signal. === val kill : int -> int -> unit

kill pid sig sends signal number sig to the process with id pid

type sigprocmask_command =
 | SIG_SETMASK
 | SIG_BLOCK
 | SIG_UNBLOCK

val sigprocmask : sigprocmask_command -> int list -> int list

sigprocmask cmd sigs changes the set of blocked signals. If cmd is SIG_SETMASK , blocked signals are set to those in the list sigs If cmd is SIG_BLOCK , the signals in sigs are added to the set of blocked signals. If cmd is SIG_UNBLOCK , the signals in sigs are removed from the set of blocked signals. sigprocmask returns the set of previously blocked signals.

val sigpending : unit -> int list

Return the set of blocked signals that are currently pending.

val sigsuspend : int list -> unit

sigsuspend sigs atomically sets the blocked signals to sig and waits for a non-ignored, non-blocked signal to be delivered. On return, the blocked signals are reset to their initial value.

val pause : unit -> unit

Wait until a non-ignored, non-blocked signal is delivered.

=== Time functions === type 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.

type 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 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 , but with resolution better than 1 second.

val gmtime : float -> tm

Convert a time in seconds, as returned by Unix.time , into a date and a time. Assumes UTC (Coordinated Universal Time), also known as GMT.

val localtime : float -> tm

Convert a time in seconds, as returned by Unix.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 Unix.time 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 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 times : unit -> process_times

Return the execution times of the process.

val utimes : string -> float -> 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 =
 | 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 (* (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. *)

The three kinds of interval timers.

type 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 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 === 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

Set the real user id and effective user id for the process.

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.

type passwd_entry = {
 pw_name : string ;
 pw_passwd : string ;
 pw_uid : int ;
 pw_gid : int ;
 pw_gecos : string ;
 pw_dir : string ;
 pw_shell : string ;
 }

Structure of entries in the passwd database.

type group_entry = {
 gr_name : string ;
 gr_passwd : string ;
 gr_gid : int ;
 gr_mem : string array ;
 }

Structure of entries in the groups database.

val getlogin : unit -> string

Return the login name of the user executing the process.

val getpwnam : string -> passwd_entry

Find an entry in passwd with the given name, or raise Not_found

val getgrnam : string -> group_entry

Find an entry in group with the given name, or raise Not_found

val getpwuid : int -> passwd_entry

Find an entry in passwd with the given user id, or raise Not_found

val getgrgid : int -> group_entry

Find an entry in group with the given group id, or raise Not_found

=== Internet addresses === type inet_addr

The abstract type of Internet addresses.

val inet_addr_of_string : string -> inet_addr

Conversions between string with the format XXX.YYY.ZZZ.TTT and Internet addresses. inet_addr_of_string raises Failure when given a string that does not match this format.

val string_of_inet_addr : inet_addr -> string

See Unix.inet_addr_of_string

val inet_addr_any : inet_addr

A special Internet address, for use only with bind , representing all the Internet addresses that the host machine possesses.

=== Sockets === type socket_domain =
 | PF_UNIX (* Unix domain *)
 | PF_INET (* Internet domain *)

The type of socket domains.

type socket_type =
 | SOCK_STREAM (* Stream socket *)
 | SOCK_DGRAM (* Datagram socket *)
 | SOCK_RAW (* Raw socket *)
 | SOCK_SEQPACKET (* Sequenced packets socket *)

The type of socket kinds, specifying the semantics of communications.

type sockaddr =
 | ADDR_UNIX of string
 | ADDR_INET of (inet_addr * 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 socket : socket_domain -> socket_type -> int -> file_descr

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 : socket_domain -> socket_type -> int -> file_descr * file_descr

Create a pair of unnamed sockets, connected together.

val accept : file_descr -> file_descr * 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 -> sockaddr -> unit

Bind a socket to an address.

val connect : file_descr -> sockaddr -> unit

Connect a socket to an address.

val listen : file_descr -> int -> unit

Set up a socket for receiving connection requests. The integer argument is the maximal number of pending requests.

type shutdown_command =
 | SHUTDOWN_RECEIVE (* Close for receiving *)
 | SHUTDOWN_SEND (* Close for sending *)
 | SHUTDOWN_ALL (* Close both *)

The type of commands for shutdown

val shutdown : file_descr -> 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 -> sockaddr

Return the address of the given socket.

val getpeername : file_descr -> sockaddr

Return the address of the host connected to the given socket.

type msg_flag =
 | MSG_OOB
 | MSG_DONTROUTE
 | MSG_PEEK (* The flags for Unix.recv , Unix.recvfrom , Unix.send and Unix.sendto

val recv : file_descr -> string -> int -> int -> msg_flag list -> int

Receive data from a connected socket.

val recvfrom : file_descr -> string -> int -> int -> msg_flag list -> int * sockaddr

Receive data from an unconnected socket.

val send : file_descr -> string -> int -> int -> msg_flag list -> int

Send data over a connected socket.

val sendto : file_descr -> string -> int -> int -> msg_flag list -> 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 (* Report whether socket listening is enabled *)

The socket options that can be consulted with Unix.getsockopt and modified with Unix.setsockopt ( true / false ) value.

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 (* Minimum number of bytes to process for output operations *)

The socket options that can be consulted with Unix.getsockopt_int and modified with Unix.setsockopt_int integer value.

type socket_optint_option =
 | SO_LINGER (* Whether to linger on closed connections that have data present, and for how long (in seconds) *)

The socket options that can be consulted with Unix.getsockopt_optint and modified with Unix.setsockopt_optint value of type int option , with None meaning ``disabled''.

type socket_float_option =
 | SO_RCVTIMEO (* Timeout for input operations *)
 | SO_SNDTIMEO (* Timeout for output operations *)

The socket options that can be consulted with Unix.getsockopt_float and modified with Unix.setsockopt_float floating-point value representing a time in seconds. The value 0 means infinite timeout.

val getsockopt : file_descr -> socket_bool_option -> bool

Return the current status of a boolean-valued option in the given socket.

val setsockopt : file_descr -> socket_bool_option -> bool -> unit

Set or clear a boolean-valued option in the given socket.

val getsockopt_int : file_descr -> socket_int_option -> int

Same as Unix.getsockopt for an integer-valued socket option.

val setsockopt_int : file_descr -> socket_int_option -> int -> unit

Same as Unix.setsockopt for an integer-valued socket option.

val getsockopt_optint : file_descr -> socket_optint_option -> int option

Same as Unix.getsockopt for a socket option whose value is an int option

val setsockopt_optint : file_descr -> socket_optint_option -> int option -> unit

Same as Unix.setsockopt for a socket option whose value is an int option

val getsockopt_float : file_descr -> socket_float_option -> float

Same as Unix.getsockopt for a socket option whose value is a floating-point number.

val setsockopt_float : file_descr -> socket_float_option -> float -> unit

Same as Unix.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 Unix.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) -> 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 Unix.establish_server never returns normally.

=== Host and protocol databases === type host_entry = {
 h_name : string ;
 h_aliases : string array ;
 h_addrtype : socket_domain ;
 h_addr_list : inet_addr array ;
 }

Structure of entries in the hosts database.

type protocol_entry = {
 p_name : string ;
 p_aliases : string array ;
 p_proto : int ;
 }

Structure of entries in the protocols database.

type service_entry = {
 s_name : string ;
 s_aliases : string array ;
 s_port : int ;
 s_proto : string ;
 }

Structure of entries in the services database.

val gethostname : unit -> string

Return the name of the local host.

val gethostbyname : string -> host_entry

Find an entry in hosts with the given name, or raise Not_found

val gethostbyaddr : inet_addr -> host_entry

Find an entry in hosts with the given address, or raise Not_found

val getprotobyname : string -> protocol_entry

Find an entry in protocols with the given name, or raise Not_found

val getprotobynumber : int -> protocol_entry

Find an entry in protocols with the given protocol number, or raise Not_found

val getservbyname : string -> string -> service_entry

Find an entry in services with the given name, or raise Not_found

val getservbyport : int -> string -> service_entry

Find an entry in services with the given service number, or raise Not_found

=== 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. === type terminal_io = { mutable c_ignbrk : bool ; (* Ignore the break condition. *) mutable c_brkint : bool ; (* Signal interrupt on break condition. *) mutable c_ignpar : bool ; (* Ignore characters with parity errors. *) mutable c_parmrk : bool ; (* Mark parity errors. *) mutable c_inpck : bool ; (* Enable parity check on input. *) mutable c_istrip : bool ; (* Strip 8th bit on input characters. *) mutable c_inlcr : bool ; (* Map NL to CR on input. *) mutable c_igncr : bool ; (* Ignore CR on input. *) mutable c_icrnl : bool ; (* Map CR to NL on input. *) mutable c_ixon : bool ; (* Recognize XON/XOFF characters on input. *) mutable c_ixoff : bool ; (* Emit XON/XOFF chars to control input flow. *) mutable c_opost : bool ; (* Enable output processing. *) mutable c_obaud : int ; (* Output baud rate (0 means close connection). *) mutable c_ibaud : int ; (* Input baud rate. *) mutable c_csize : int ; (* Number of bits per character (5-8). *) mutable c_cstopb : int ; (* Number of stop bits (1-2). *) mutable c_cread : bool ; (* Reception is enabled. *) mutable c_parenb : bool ; (* Enable parity generation and detection. *) mutable c_parodd : bool ; (* Specify odd parity instead of even. *) mutable c_hupcl : bool ; (* Hang up on last close. *) mutable c_clocal : bool ; (* Ignore modem status lines. *) mutable c_isig : bool ; (* Generate signal on INTR, QUIT, SUSP. *) mutable c_icanon : bool ; (* Enable canonical processing (line buffering and editing) *) mutable c_noflsh : bool ; (* Disable flush after INTR, QUIT, SUSP. *) mutable c_echo : bool ; (* Echo input characters. *) mutable c_echoe : bool ; (* Echo ERASE (to erase previous character). *) mutable c_echok : bool ; (* Echo KILL (to erase the current line). *) mutable c_echonl : bool ; (* Echo NL even if c_echo is not set. *) mutable c_vintr : char ; (* Interrupt character (usually ctrl-C). *) mutable c_vquit : char ; (* Quit character (usually ctrl-. *) mutable c_verase : char ; (* Erase character (usually DEL or ctrl-H). *) mutable c_vkill : char ; (* Kill line character (usually ctrl-U). *) mutable c_veof : char ; (* End-of-file character (usually ctrl-D). *) mutable c_veol : char ; (* Alternate end-of-line char. (usually none). *) mutable c_vmin : int ; (* Minimum number of characters to read before the read request is satisfied. *) mutable c_vtime : int ; (* Maximum read wait (in 0.1s units). *) mutable c_vstart : char ; (* Start character (usually ctrl-Q). *) mutable c_vstop : char ; (* Stop character (usually ctrl-S). *)
 }

val tcgetattr : file_descr -> terminal_io

Return the status of the terminal referred to by the given file descriptor.

type setattr_when =
 | TCSANOW
 | TCSADRAIN
 | TCSAFLUSH

val tcsetattr : file_descr -> setattr_when -> terminal_io -> unit

Set the status of the terminal referred to by the given file descriptor. The second argument indicates when the status change takes place: immediately ( TCSANOW ), when all pending output has been transmitted ( TCSADRAIN ), or after flushing all input that has been received but not read ( TCSAFLUSH ). TCSADRAIN is recommended when changing the output parameters; TCSAFLUSH , when changing the input parameters.

val tcsendbreak : file_descr -> int -> unit

Send a break condition on the given file descriptor. The second argument is the duration of the break, in 0.1s units; 0 means standard duration (0.25s).

val tcdrain : file_descr -> unit

Waits until all output written on the given file descriptor has been transmitted.

type flush_queue =
 | TCIFLUSH
 | TCOFLUSH
 | TCIOFLUSH

val tcflush : file_descr -> flush_queue -> unit

Discard data written on the given file descriptor but not yet transmitted, or data received but not yet read, depending on the second argument: TCIFLUSH flushes data received but not read, TCOFLUSH flushes data written but not transmitted, and TCIOFLUSH flushes both.

type flow_action =
 | TCOOFF
 | TCOON
 | TCIOFF
 | TCION

val tcflow : file_descr -> flow_action -> unit

Suspend or restart reception or transmission of data on the given file descriptor, depending on the second argument: TCOOFF suspends output, TCOON restarts output, TCIOFF transmits a STOP character to suspend input, and TCION transmits a START character to restart input.

val setsid : unit -> int

Put the calling process in a new session and detach it from its controlling terminal.