Module U = Core.Std.Unix

Return a string describing the given error code.

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.

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.

Return the process environment, as an array of strings with the format ``variable=value''.

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.

unsetenv name deletes the variable name from the environment.

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

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 determines the environment when prog is executed.

The first element in args should be the program itself; the correct way to call exec is:

    exec ~prog ~args:[ prog; arg1; arg2; ...] ()    

fork_exec ~prog ~args ?use_path ?env () forks and execs prog with args in the child process, returning the child PID to the parent.

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.

waitpid pid waits for child process pid to terminate, and returns its exit status. waitpid_exn is like waitpid, except it only returns if the child exits with status zero, and raises if the child terminates in any other way.

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.

Return the pid of the process.

Return the pid of the parent process.

Return the pid of the parent process, if you're really sure you're never going to be the init process.

Get the numeric ID of the current thread, e.g. for identifying it in top(1).

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.

File descriptor for standard input.

File descriptor for standard output.

File descriptor for standard standard error.

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.

fcntl_getfl fd gets the current flags for fd from the open-file-descriptor table via the system call fcntl(fd, F_GETFL). See "man fcntl".

fcntl_setfl fd flags sets the flags for fd in the open-file-descriptor table via the system call fcntl(fd, F_SETFL, flags). See "man fcntl". As per the Linux man page, on Linux this only allows append and nonblock to be set.

Close a file descriptor.

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).

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.

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.

Same as write but ensures that all errors are reported and that no character has ever been written when an error is reported.

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.

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.

Return the descriptor corresponding to an input channel.

Return the descriptor corresponding to an output channel.

Set the current position for a file descriptor

Truncates the named file to the given size.

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

Return the information for the named file.

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

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

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.

flock fd cmd places or releases a lock on the fd as per the flock C call of the same name.

Return true if the given file descriptor refers to a terminal or console window, false otherwise.

Removes the named file

Removes the named file or directory

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

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.

Change the permissions of the named file.

Change the permissions of an opened file.

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

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

Set the process creation mask, and return the previous mask.

Check that the process has the given permissions over the named file.

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

dup2 ~src ~dst duplicates src to dst, closing dst if already opened.

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.

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

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.

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

Create a directory. The permissions of the created directory are (perm & ~umask & 0777). The default perm is 0777.

Create a directory recursively. The permissions of the created directory are those granted by mkdir ~perm.

Remove an empty directory.

Change the process working directory.

Return the name of the current working directory.

Change the process root directory.

Open a descriptor on a directory

Return the next entry in a directory.

Reposition the descriptor to the beginning of the directory

Close a directory descriptor.

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.

Create a named pipe with the given permissions.

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.

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.

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.

See UnixLabels.open_process_in.

See UnixLabels.open_process_in.

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

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

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

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

symlink source dest creates the file dest as a symbolic link to the file source.

Read the contents of a link.

Wait until some input/output operations become possible on some channels. The three list arguments are a set of descriptors to check for reading, for writing, or for exceptional conditions. ~timeout is the maximal timeout. The result is composed of three sets of descriptors: those ready for reading, ready for writing, and over which an exceptional condition is pending.

Setting restart to true means that we want select to restart automatically on EINTR (instead of propagating the exception)...

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

Return the current time since 00:00:00 GMT, Jan. 1, 1970, in seconds.

Same as time above, but with resolution better than 1 second.

Convert a time in seconds, as returned by UnixLabels.time, into a date and a time. Assumes UTC.

Convert a UTC time in a tm record to a time in seconds

Convert a time in seconds, as returned by UnixLabels.time, into a date and a time. Assumes the local time zone.

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.

Convert a date and time, specified by the tm argument, into a formatted string. See 'man strftime' for format options.

Given a format string, convert a corresponding string to a date and time See 'man strptime' for format options.

Schedule a SIGALRM signal after the given number of seconds.

Stop execution for the given number of seconds.

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.

Return the execution times of the process.

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.

Return the current status of the given interval timer.

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.

Return the user id of the user executing the process.

Return the effective user id under which the process runs.

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.

Return the group id of the user executing the process.

Return the effective group id under which the process runs.

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

Return the login name of the user executing the process.

Return the socket domain adequate for the given socket address.

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.

Create a pair of unnamed sockets, connected together.

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.

Bind a socket to an address.

Connect a socket to an address.

Set up a socket for receiving connection requests. The integer argument is the number of pending requests that will be established and queued for accept. Depending on operating system, version, and configuration, subsequent connections may be refused actively (as with RST), ignored, or effectively established and queued anyway.

Because handling of excess connections varies, it is most robust for applications to accept and close excess connections if they can. To be sure the client receives an RST rather than an orderly shutdown, you can setsockopt_optint file_descr SO_LINGER (Some 0) before closing.

In Linux, for example, the system configuration parameters tcp_max_syn_backlog, tcp_abort_on_overflow, and syncookies can all affect connection queuing behavior.

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).

Return the address of the given socket.

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

Receive data from a connected socket.

Receive data from an unconnected socket.

Send data over a connected socket.

Send data over an unconnected socket.

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

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

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

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

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

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

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

Same as UnixLabels.setsockopt for a socket option whose value is a floating-point number.

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.

``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.

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.

Return the name of the local host.

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).

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.

Get a sockaddr from a hostname or IP, and a port

Set a timeout for a socket associated with an in_channel

Set a timeout for a socket associated with an out_channel

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.

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.

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.

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.

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.

writev fd ?count iovecs like 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.

mkstemp prefix creates and opens a unique temporary file with prefix, automatically appending a suffix of six random characters to make the name unique. Unlike C's mkstemp, prefix should not include six X's at the end.

mkdtemp prefix creates a temporary directory with prefix, automatically appending a suffix of six random characters to make the name unique.

getgrouplist user group returns the list of groups to which user belongs. See 'man getgrouplist'.

Return the list of groups to which the user executing the process belongs.

mcast_join ?ifname sock addr join a multicast group at addr with socket sock, from source at source if specified, optionally using network interface ifname.

mcast_leave ?ifname sock addr leaves a multicast group at addr with socket sock, optionally using network interface ifname.

get_mcast_ttl sock reads the time-to-live value of outgoing multicast packets for socket sock.

set_mcast_ttl sock ttl sets the time-to-live value of outgoing multicast packets for socket sock to ttl.

get_mcast_loop sock reads the boolean argument that determines whether sent multicast packets are looped back to local sockets.

set_mcast_loop sock loop sets the boolean argument that determines whether sent multicast packets are looped back to local sockets.

set_mcast_ifname sock "eth0" sets outgoing multicast traffic on IPv4 UDP socket sock to go out through interface eth0.

This uses setsockopt with IP_MULTICAST_IF and applies to multicast traffic. For non-multicast applications, see Core.Linux_ext.bind_to_interface.