Allow any pending output from subprocesses to be read by Emacs.
It is read into the process' buffers or given to their filter functions.
Non-nil arg PROCESS means do not return until some output has been received
from PROCESS.

Non-nil second arg SECONDS and third arg MILLISEC are number of seconds
and milliseconds to wait; return after that much time whether or not
there is any subprocess output.  If SECONDS is a floating point number,
it specifies a fractional number of seconds to wait.
The MILLISEC argument is obsolete and should be avoided.

If optional fourth arg JUST-THIS-ONE is non-nil, only accept output
from PROCESS, suspending reading output from other processes.
If JUST-THIS-ONE is an integer, don't run any timers either.
Return non-nil if we received any output before the timeout expired.

Continue process PROCESS.  May be process or name of one.
See function `interrupt-process' for more details on usage.
If PROCESS is a network or serial process, resume handling of incoming
traffic.

Delete PROCESS: kill it and forget about it immediately.
PROCESS may be a process, a buffer, the name of a process or buffer, or
nil, indicating the current buffer's process.

Convert network ADDRESS from internal format to a string.
A 4 or 5 element vector represents an IPv4 address (with port number).
An 8 or 9 element vector represents an IPv6 address (with port number).
If optional second argument OMIT-PORT is non-nil, don't include a port
number in the string, even when present in ADDRESS.
Returns nil if format of ADDRESS is invalid.

Return the (or a) process associated with BUFFER.
BUFFER may be a buffer or the name of one.

Return the process named NAME, or nil if there is none.

Interrupt process PROCESS.
PROCESS may be a process, a buffer, or the name of a process or buffer.
No arg or nil means current buffer's process.
Second arg CURRENT-GROUP non-nil means send signal to
the current process-group of the process's controlling terminal
rather than to the process's own process group.
If the process is a shell, this means interrupt current subjob
rather than the shell.

If CURRENT-GROUP is `lambda', and if the shell owns the terminal,
don't send the signal.

Kill process PROCESS.  May be process or name of one.
See function `interrupt-process' for more details on usage.

Return a list of numerical process IDs of all running processes.
If this functionality is unsupported, return nil.

See `process-attributes' for getting attributes of a process given its ID.

Create and return a network server or client process.

In Emacs, network connections are represented by process objects, so
input and output work as for subprocesses and `delete-process' closes
a network connection.  However, a network process has no process id,
it cannot be signaled, and the status codes are different from normal
processes.

Arguments are specified as keyword/argument pairs.  The following
arguments are defined:

:name NAME -- NAME is name for process.  It is modified if necessary
to make it unique.

:buffer BUFFER -- BUFFER is the buffer (or buffer-name) to associate
with the process.  Process output goes at end of that buffer, unless
you specify an output stream or filter function to handle the output.
BUFFER may be also nil, meaning that this process is not associated
with any buffer.

:host HOST -- HOST is name of the host to connect to, or its IP
address.  The symbol `local' specifies the local host.  If specified
for a server process, it must be a valid name or address for the local
host, and only clients connecting to that address will be accepted.

:service SERVICE -- SERVICE is name of the service desired, or an
integer specifying a port number to connect to.  If SERVICE is t,
a random port number is selected for the server.  (If Emacs was
compiled with getaddrinfo, a port number can also be specified as a
string, e.g. "80", as well as an integer.  This is not portable.)

:type TYPE -- TYPE is the type of connection.  The default (nil) is a
stream type connection, `datagram' creates a datagram type connection,
`seqpacket' creates a reliable datagram connection.

:family FAMILY -- FAMILY is the address (and protocol) family for the
service specified by HOST and SERVICE.  The default (nil) is to use
whatever address family (IPv4 or IPv6) that is defined for the host
and port number specified by HOST and SERVICE.  Other address families
supported are:
  local -- for a local (i.e. UNIX) address specified by SERVICE.
  ipv4  -- use IPv4 address family only.
  ipv6  -- use IPv6 address family only.

:local ADDRESS -- ADDRESS is the local address used for the connection.
This parameter is ignored when opening a client process. When specified
for a server process, the FAMILY, HOST and SERVICE args are ignored.

:remote ADDRESS -- ADDRESS is the remote partner's address for the
connection.  This parameter is ignored when opening a stream server
process.  For a datagram server process, it specifies the initial
setting of the remote datagram address.  When specified for a client
process, the FAMILY, HOST, and SERVICE args are ignored.

The format of ADDRESS depends on the address family:
- An IPv4 address is represented as an vector of integers [A B C D P]
corresponding to numeric IP address A.B.C.D and port number P.
- A local address is represented as a string with the address in the
local address space.
- An "unsupported family" address is represented by a cons (F . AV)
where F is the family number and AV is a vector containing the socket
address data with one element per address data byte.  Do not rely on
this format in portable code, as it may depend on implementation
defined constants, data sizes, and data structure alignment.

:coding CODING -- If CODING is a symbol, it specifies the coding
system used for both reading and writing for this process.  If CODING
is a cons (DECODING . ENCODING), DECODING is used for reading, and
ENCODING is used for writing.

:nowait BOOL -- If BOOL is non-nil for a stream type client process,
return without waiting for the connection to complete; instead, the
sentinel function will be called with second arg matching "open" (if
successful) or "failed" when the connect completes.  Default is to use
a blocking connect (i.e. wait) for stream type connections.

:noquery BOOL -- Query the user unless BOOL is non-nil, and process is
running when Emacs is exited.

:stop BOOL -- Start process in the `stopped' state if BOOL non-nil.
In the stopped state, a server process does not accept new
connections, and a client process does not handle incoming traffic.
The stopped state is cleared by `continue-process' and set by
`stop-process'.

:filter FILTER -- Install FILTER as the process filter.

:filter-multibyte BOOL -- If BOOL is non-nil, strings given to the
process filter are multibyte, otherwise they are unibyte.
If this keyword is not specified, the strings are multibyte if
the default value of `enable-multibyte-characters' is non-nil.

:sentinel SENTINEL -- Install SENTINEL as the process sentinel.

:log LOG -- Install LOG as the server process log function.  This
function is called when the server accepts a network connection from a
client.  The arguments are SERVER, CLIENT, and MESSAGE, where SERVER
is the server process, CLIENT is the new process for the connection,
and MESSAGE is a string.

:plist PLIST -- Install PLIST as the new process' initial plist.

:server QLEN -- if QLEN is non-nil, create a server process for the
specified FAMILY, SERVICE, and connection type (stream or datagram).
If QLEN is an integer, it is used as the max. length of the server's
pending connection queue (also known as the backlog); the default
queue length is 5.  Default is to create a client process.

The following network options can be specified for this connection:

:broadcast BOOL    -- Allow send and receive of datagram broadcasts.
:dontroute BOOL    -- Only send to directly connected hosts.
:keepalive BOOL    -- Send keep-alive messages on network stream.
:linger BOOL or TIMEOUT -- Send queued messages before closing.
:oobinline BOOL    -- Place out-of-band data in receive data stream.
:priority INT      -- Set protocol defined priority for sent packets.
:reuseaddr BOOL    -- Allow reusing a recently used local address
                      (this is allowed by default for a server process).
:bindtodevice NAME -- bind to interface NAME.  Using this may require
                      special privileges on some systems.

Consult the relevant system programmer's manual pages for more
information on using these options.


A server process will listen for and accept connections from clients.
When a client connection is accepted, a new network process is created
for the connection with the following parameters:

- The client's process name is constructed by concatenating the server
process' NAME and a client identification string.
- If the FILTER argument is non-nil, the client process will not get a
separate process buffer; otherwise, the client's process buffer is a newly
created buffer named after the server process' BUFFER name or process
NAME concatenated with the client identification string.
- The connection type and the process filter and sentinel parameters are
inherited from the server process' TYPE, FILTER and SENTINEL.
- The client process' contact info is set according to the client's
addressing information (typically an IP address and a port number).
- The client process' plist is initialized from the server's plist.

Notice that the FILTER and SENTINEL args are never used directly by
the server process.  Also, the BUFFER argument is not used directly by
the server process, but via the optional :log function, accepted (and
failed) connections may be logged in the server process' buffer.

The original argument list, modified with the actual connection
information, is available via the `process-contact' function.

Create and return a serial port process.

In Emacs, serial port connections are represented by process objects,
so input and output work as for subprocesses, and `delete-process'
closes a serial port connection.  However, a serial process has no
process id, it cannot be signaled, and the status codes are different
from normal processes.

`make-serial-process' creates a process and a buffer, on which you
probably want to use `process-send-string'.  Try M-x serial-term for
an interactive terminal.  See below for examples.

Arguments are specified as keyword/argument pairs.  The following
arguments are defined:

:port PORT -- (mandatory) PORT is the path or name of the serial port.
For example, this could be "/dev/ttyS0" on Unix.  On Windows, this
could be "COM1", or "\\.\COM10" for ports higher than COM9 (double
the backslashes in strings).

:speed SPEED -- (mandatory) is handled by `serial-process-configure',
which this function calls.

:name NAME -- NAME is the name of the process.  If NAME is not given,
the value of PORT is used.

:buffer BUFFER -- BUFFER is the buffer (or buffer-name) to associate
with the process.  Process output goes at the end of that buffer,
unless you specify an output stream or filter function to handle the
output.  If BUFFER is not given, the value of NAME is used.

:coding CODING -- If CODING is a symbol, it specifies the coding
system used for both reading and writing for this process.  If CODING
is a cons (DECODING . ENCODING), DECODING is used for reading, and
ENCODING is used for writing.

:noquery BOOL -- When exiting Emacs, query the user if BOOL is nil and
the process is running.  If BOOL is not given, query before exiting.

:stop BOOL -- Start process in the `stopped' state if BOOL is non-nil.
In the stopped state, a serial process does not accept incoming data,
but you can send outgoing data.  The stopped state is cleared by
`continue-process' and set by `stop-process'.

:filter FILTER -- Install FILTER as the process filter.

:sentinel SENTINEL -- Install SENTINEL as the process sentinel.

:plist PLIST -- Install PLIST as the initial plist of the process.

:bytesize
:parity
:stopbits
:flowcontrol
-- This function calls `serial-process-configure' to handle these
arguments.

The original argument list, possibly modified by later configuration,
is available via the function `process-contact'.

Examples:

(make-serial-process :port "/dev/ttyS0" :speed 9600)

(make-serial-process :port "COM1" :speed 115200 :stopbits 2)

(make-serial-process :port "\\.\COM13" :speed 1200 :bytesize 7 :parity 'odd)

(make-serial-process :port "/dev/tty.BlueConsole-SPP-1" :speed nil)

Return information about network interface named IFNAME.
The return value is a list (ADDR BCAST NETMASK HWADDR FLAGS),
where ADDR is the layer 3 address, BCAST is the layer 3 broadcast address,
NETMASK is the layer 3 network mask, HWADDR is the layer 2 address, and
FLAGS is the current flags of the interface.

Return an alist of all network interfaces and their network address.
Each element is a cons, the car of which is a string containing the
interface name, and the cdr is the network address in internal
format; see the description of ADDRESS in `make-network-process'.

Return attributes of the process given by its PID, a number.

Value is an alist where each element is a cons cell of the form

    (KEY . VALUE)

If this functionality is unsupported, the value is nil.

See `list-system-processes' for getting a list of all process IDs.

The KEYs of the attributes that this function may return are listed
below, together with the type of the associated VALUE (in parentheses).
Not all platforms support all of these attributes; unsupported
attributes will not appear in the returned alist.
Unless explicitly indicated otherwise, numbers can have either
integer or floating point values.

 euid    -- Effective user User ID of the process (number)
 user    -- User name corresponding to euid (string)
 egid    -- Effective user Group ID of the process (number)
 group   -- Group name corresponding to egid (string)
 comm    -- Command name (executable name only) (string)
 state   -- Process state code, such as "S", "R", or "T" (string)
 ppid    -- Parent process ID (number)
 pgrp    -- Process group ID (number)
 sess    -- Session ID, i.e. process ID of session leader (number)
 ttname  -- Controlling tty name (string)
 tpgid   -- ID of foreground process group on the process's tty (number)
 minflt  -- number of minor page faults (number)
 majflt  -- number of major page faults (number)
 cminflt -- cumulative number of minor page faults (number)
 cmajflt -- cumulative number of major page faults (number)
 utime   -- user time used by the process, in the (HIGH LOW USEC) format
 stime   -- system time used by the process, in the (HIGH LOW USEC) format
 time    -- sum of utime and stime, in the (HIGH LOW USEC) format
 cutime  -- user time used by the process and its children, (HIGH LOW USEC)
 cstime  -- system time used by the process and its children, (HIGH LOW USEC)
 ctime   -- sum of cutime and cstime, in the (HIGH LOW USEC) format
 pri     -- priority of the process (number)
 nice    -- nice value of the process (number)
 thcount -- process thread count (number)
 start   -- time the process started, in the (HIGH LOW USEC) format
 vsize   -- virtual memory size of the process in KB's (number)
 rss     -- resident set size of the process in KB's (number)
 etime   -- elapsed time the process is running, in (HIGH LOW USEC) format
 pcpu    -- percents of CPU time used by the process (floating-point number)
 pmem    -- percents of total physical memory used by process's resident set
              (floating-point number)
 args    -- command line which invoked the process (string).

Return the buffer PROCESS is associated with.
Output from PROCESS is inserted in this buffer unless PROCESS has a filter.

Return a cons of coding systems for decoding and encoding of PROCESS.

Return the command that was executed to start PROCESS.
This is a list of strings, the first string being the program executed
and the rest of the strings being the arguments given to it.
For a network or serial process, this is nil (process is running) or t
(process is stopped).

Return the contact info of PROCESS; t for a real child.
For a network or serial connection, the value depends on the optional
KEY arg.  If KEY is nil, value is a cons cell of the form (HOST
SERVICE) for a network connection or (PORT SPEED) for a serial
connection.  If KEY is t, the complete contact information for the
connection is returned, else the specific value for the keyword KEY is
returned.  See `make-network-process' or `make-serial-process' for a
list of keywords.

Get the current datagram address associated with PROCESS.

Return the exit status of PROCESS or the signal number that killed it.
If PROCESS has not yet exited or died, return 0.

Returns the filter function of PROCESS; nil if none.
See `set-process-filter' for more info on filter functions.

This function is obsolete since 23.1.

Return t if a multibyte string is given to PROCESS's filter.

Return the process id of PROCESS.
This is the pid of the external process which PROCESS uses or talks to.
For a network connection, this value is nil.

Return the value of inherit-coding-system flag for PROCESS.
If this flag is t, `buffer-file-coding-system' of the buffer
associated with PROCESS will inherit the coding system used to decode
the process output.

Return a list of all processes.

Return the marker for the end of the last output from PROCESS.

Return the name of PROCESS, as a string.
This is the name of the program invoked in PROCESS,
possibly modified to make it unique among process names.

Return the plist of PROCESS.

Return the current value of query-on-exit flag for PROCESS.

Return t if PROCESS has given the terminal to a child.
If the operating system does not make it possible to find out,
return t unconditionally.

Make PROCESS see end-of-file in its input.
EOF comes after any text already sent to it.
PROCESS may be a process, a buffer, the name of a process or buffer, or
nil, indicating the current buffer's process.
If PROCESS is a network connection, or is a process communicating
through a pipe (as opposed to a pty), then you cannot send any more
text to PROCESS after you call this function.
If PROCESS is a serial process, wait until all output written to the
process has been transmitted to the serial port.

Send current contents of region as input to PROCESS.
PROCESS may be a process, a buffer, the name of a process or buffer, or
nil, indicating the current buffer's process.
Called from program, takes three arguments, PROCESS, START and END.
If the region is more than 500 characters long,
it is sent in several bunches.  This may happen even for shorter regions.
Output from processes can arrive in between bunches.

Send PROCESS the contents of STRING as input.
PROCESS may be a process, a buffer, the name of a process or buffer, or
nil, indicating the current buffer's process.
If STRING is more than 500 characters long,
it is sent in several bunches.  This may happen even for shorter strings.
Output from processes can arrive in between bunches.

Return the sentinel of PROCESS; nil if none.
See `set-process-sentinel' for more info on sentinels.

Return the status of PROCESS.
The returned value is one of the following symbols:
run  -- for a process that is running.
stop -- for a process stopped but continuable.
exit -- for a process that has exited.
signal -- for a process that has got a fatal signal.
open -- for a network stream connection that is open.
listen -- for a network stream server that is listening.
closed -- for a network stream connection that is closed.
connect -- when waiting for a non-blocking connection to complete.
failed -- when a non-blocking connection has failed.
nil -- if arg is a process name and no such process exists.
PROCESS may be a process, a buffer, the name of a process, or
nil, indicating the current buffer's process.

Return the name of the terminal PROCESS uses, or nil if none.
This is the terminal that the process itself reads and writes on,
not the name of the pty that Emacs uses to talk with that terminal.

Return the connection type of PROCESS.
The value is either the symbol `real', `network', or `serial'.
PROCESS may be a process, a buffer, the name of a process or buffer, or
nil, indicating the current buffer's process.

Return t if OBJECT is a process.

Send QUIT signal to process PROCESS.  May be process or name of one.
See function `interrupt-process' for more details on usage.

Configure speed, bytesize, etc. of a serial process.

Arguments are specified as keyword/argument pairs.  Attributes that
are not given are re-initialized from the process's current
configuration (available via the function `process-contact') or set to
reasonable default values.  The following arguments are defined:

:process PROCESS
:name NAME
:buffer BUFFER
:port PORT
-- Any of these arguments can be given to identify the process that is
to be configured.  If none of these arguments is given, the current
buffer's process is used.

:speed SPEED -- SPEED is the speed of the serial port in bits per
second, also called baud rate.  Any value can be given for SPEED, but
most serial ports work only at a few defined values between 1200 and
115200, with 9600 being the most common value.  If SPEED is nil, the
serial port is not configured any further, i.e., all other arguments
are ignored.  This may be useful for special serial ports such as
Bluetooth-to-serial converters which can only be configured through AT
commands.  A value of nil for SPEED can be used only when passed
through `make-serial-process' or `serial-term'.

:bytesize BYTESIZE -- BYTESIZE is the number of bits per byte, which
can be 7 or 8.  If BYTESIZE is not given or nil, a value of 8 is used.

:parity PARITY -- PARITY can be nil (don't use parity), the symbol
`odd' (use odd parity), or the symbol `even' (use even parity).  If
PARITY is not given, no parity is used.

:stopbits STOPBITS -- STOPBITS is the number of stopbits used to
terminate a byte transmission.  STOPBITS can be 1 or 2.  If STOPBITS
is not given or nil, 1 stopbit is used.

:flowcontrol FLOWCONTROL -- FLOWCONTROL determines the type of
flowcontrol to be used, which is either nil (don't use flowcontrol),
the symbol `hw' (use RTS/CTS hardware flowcontrol), or the symbol `sw'
(use XON/XOFF software flowcontrol).  If FLOWCONTROL is not given, no
flowcontrol is used.

`serial-process-configure' is called by `make-serial-process' for the
initial configuration of the serial port.

Examples:

(serial-process-configure :process "/dev/ttyS0" :speed 1200)

(serial-process-configure
    :buffer "COM1" :stopbits 1 :parity 'odd :flowcontrol 'hw)

(serial-process-configure :port "\\.\COM13" :bytesize 7)

For network process PROCESS set option OPTION to value VALUE.
See `make-network-process' for a list of options and values.
If optional fourth arg NO-ERROR is non-nil, don't signal an error if
OPTION is not a supported option, return nil instead; otherwise return t.

Set buffer associated with PROCESS to BUFFER (a buffer, or nil).
Return BUFFER.

Set coding systems of PROCESS to DECODING and ENCODING.
DECODING will be used to decode subprocess output and ENCODING to
encode subprocess input.

Set the datagram address for PROCESS to ADDRESS.
Returns nil upon error setting address, ADDRESS otherwise.

Give PROCESS the filter function FILTER; nil means no filter.
A value of t means stop accepting output from the process.

When a process has a filter, its buffer is not used for output.
Instead, each time it does output, the entire string of output is
passed to the filter.

The filter gets two arguments: the process and the string of output.
The string argument is normally a multibyte string, except:
- if the process' input coding system is no-conversion or raw-text,
  it is a unibyte string (the non-converted input), or else
- if `default-enable-multibyte-characters' is nil, it is a unibyte
  string (the result of converting the decoded input multibyte
  string to unibyte with `string-make-unibyte').

This function is obsolete since 23.1.

Set multibyteness of the strings given to PROCESS's filter.
If FLAG is non-nil, the filter is given multibyte strings.
If FLAG is nil, the filter is given unibyte strings.  In this case,
all character code conversion except for end-of-line conversion is
suppressed.

Determine whether buffer of PROCESS will inherit coding-system.
If the second argument FLAG is non-nil, then the variable
`buffer-file-coding-system' of the buffer associated with PROCESS
will be bound to the value of the coding system used to decode
the process output.

This is useful when the coding system specified for the process buffer
leaves either the character code conversion or the end-of-line conversion
unspecified, or if the coding system used to decode the process output
is more appropriate for saving the process buffer.

Binding the variable `inherit-process-coding-system' to non-nil before
starting the process is an alternative way of setting the inherit flag
for the process which will run.

This function returns FLAG.

Replace the plist of PROCESS with PLIST.  Returns PLIST.

Specify if query is needed for PROCESS when Emacs is exited.
If the second argument FLAG is non-nil, Emacs will query the user before
exiting or killing a buffer if PROCESS is running.  This function
returns FLAG.

Give PROCESS the sentinel SENTINEL; nil for none.
The sentinel is called as a function when the process changes state.
It gets two arguments: the process, and a string describing the change.

Tell PROCESS that it has logical window size HEIGHT and WIDTH.

Send PROCESS the signal with code SIGCODE.
PROCESS may also be a number specifying the process id of the
process to signal; in this case, the process need not be a child of
this Emacs.
SIGCODE may be an integer, or a symbol whose name is a signal name.

Start a program in a subprocess.  Return the process object for it.
NAME is name for process.  It is modified if necessary to make it unique.
BUFFER is the buffer (or buffer name) to associate with the process.

Process output (both standard output and standard error streams) goes
at end of BUFFER, unless you specify an output stream or filter
function to handle the output.  BUFFER may also be nil, meaning that
this process is not associated with any buffer.

PROGRAM is the program file name.  It is searched for in `exec-path'
(which see).  If nil, just associate a pty with the buffer.  Remaining
arguments are strings to give program as arguments.

If you want to separate standard output from standard error, invoke
the command through a shell and redirect one of them using the shell
syntax.

Stop process PROCESS.  May be process or name of one.
See function `interrupt-process' for more details on usage.
If PROCESS is a network or serial process, inhibit handling of incoming
traffic.

Returns non-nil if Emacs is waiting for input from the user.
This is intended for use by asynchronous process output filters and sentinels.