summaryrefslogtreecommitdiffstats
path: root/Doc/lib/libselect.tex
diff options
context:
space:
mode:
authorGeorg Brandl <georg@python.org>2007-08-15 14:26:55 (GMT)
committerGeorg Brandl <georg@python.org>2007-08-15 14:26:55 (GMT)
commitf56181ff53ba00b7bed3997a4dccd9a1b6217b57 (patch)
tree1200947a7ffc78c2719831e4c7fd900a8ab01368 /Doc/lib/libselect.tex
parentaf62d9abfb78067a54c769302005f952ed999f6a (diff)
downloadcpython-f56181ff53ba00b7bed3997a4dccd9a1b6217b57.zip
cpython-f56181ff53ba00b7bed3997a4dccd9a1b6217b57.tar.gz
cpython-f56181ff53ba00b7bed3997a4dccd9a1b6217b57.tar.bz2
Delete the LaTeX doc tree.
Diffstat (limited to 'Doc/lib/libselect.tex')
-rw-r--r--Doc/lib/libselect.tex132
1 files changed, 0 insertions, 132 deletions
diff --git a/Doc/lib/libselect.tex b/Doc/lib/libselect.tex
deleted file mode 100644
index 69583d4..0000000
--- a/Doc/lib/libselect.tex
+++ /dev/null
@@ -1,132 +0,0 @@
-\section{\module{select} ---
- Waiting for I/O completion}
-
-\declaremodule{builtin}{select}
-\modulesynopsis{Wait for I/O completion on multiple streams.}
-
-
-This module provides access to the \cfunction{select()}
-and \cfunction{poll()} functions
-available in most operating systems. Note that on Windows, it only
-works for sockets; on other operating systems, it also works for other
-file types (in particular, on \UNIX, it works on pipes). It cannot
-be used on regular files to determine whether a file has grown since
-it was last read.
-
-The module defines the following:
-
-\begin{excdesc}{error}
-The exception raised when an error occurs. The accompanying value is
-a pair containing the numeric error code from \cdata{errno} and the
-corresponding string, as would be printed by the \C{} function
-\cfunction{perror()}.
-\end{excdesc}
-
-\begin{funcdesc}{poll}{}
-(Not supported by all operating systems.) Returns a polling object,
-which supports registering and unregistering file descriptors, and
-then polling them for I/O events;
-see section~\ref{poll-objects} below for the methods supported by
-polling objects.
-\end{funcdesc}
-
-\begin{funcdesc}{select}{iwtd, owtd, ewtd\optional{, timeout}}
-This is a straightforward interface to the \UNIX{} \cfunction{select()}
-system call. The first three arguments are sequences of `waitable
-objects': either integers representing file descriptors or
-objects with a parameterless method named \method{fileno()} returning
-such an integer. The three sequences of waitable objects are for input,
-output and `exceptional conditions', respectively. Empty sequences are
-allowed, but acceptance of three empty sequences is platform-dependent.
-(It is known to work on \UNIX{} but not on Windows.) The optional
-\var{timeout} argument specifies a time-out as a floating point number
-in seconds. When the \var{timeout} argument is omitted the function
-blocks until at least one file descriptor is ready. A time-out value
-of zero specifies a poll and never blocks.
-
-The return value is a triple of lists of objects that are ready:
-subsets of the first three arguments. When the time-out is reached
-without a file descriptor becoming ready, three empty lists are
-returned.
-
-Among the acceptable object types in the sequences are Python file
-objects (e.g. \code{sys.stdin}, or objects returned by
-\function{open()} or \function{os.popen()}), socket objects
-returned by \function{socket.socket()}.%
-\withsubitem{(in module socket)}{\ttindex{socket()}}
-\withsubitem{(in module os)}{\ttindex{popen()}}
-You may also define a \dfn{wrapper} class yourself, as long as it has
-an appropriate \method{fileno()} method (that really returns a file
-descriptor, not just a random integer).
-\note{File objects on Windows are not acceptable, but sockets
-are.\index{WinSock} On Windows, the underlying \cfunction{select()}
-function is provided by the WinSock library, and does not handle file
-descriptors that don't originate from WinSock.}
-\end{funcdesc}
-
-\subsection{Polling Objects
- \label{poll-objects}}
-
-The \cfunction{poll()} system call, supported on most \UNIX{} systems,
-provides better scalability for network servers that service many,
-many clients at the same time.
-\cfunction{poll()} scales better because the system call only
-requires listing the file descriptors of interest, while \cfunction{select()}
-builds a bitmap, turns on bits for the fds of interest, and then
-afterward the whole bitmap has to be linearly scanned again.
-\cfunction{select()} is O(highest file descriptor), while
-\cfunction{poll()} is O(number of file descriptors).
-
-\begin{methoddesc}[poll]{register}{fd\optional{, eventmask}}
-Register a file descriptor with the polling object. Future calls to
-the \method{poll()} method will then check whether the file descriptor
-has any pending I/O events. \var{fd} can be either an integer, or an
-object with a \method{fileno()} method that returns an integer. File
-objects implement
-\method{fileno()}, so they can also be used as the argument.
-
-\var{eventmask} is an optional bitmask describing the type of events you
-want to check for, and can be a combination of the constants
-\constant{POLLIN}, \constant{POLLPRI}, and \constant{POLLOUT},
-described in the table below. If not specified, the default value
-used will check for all 3 types of events.
-
-\begin{tableii}{l|l}{constant}{Constant}{Meaning}
- \lineii{POLLIN}{There is data to read}
- \lineii{POLLPRI}{There is urgent data to read}
- \lineii{POLLOUT}{Ready for output: writing will not block}
- \lineii{POLLERR}{Error condition of some sort}
- \lineii{POLLHUP}{Hung up}
- \lineii{POLLNVAL}{Invalid request: descriptor not open}
-\end{tableii}
-
-Registering a file descriptor that's already registered is not an
-error, and has the same effect as registering the descriptor exactly
-once.
-\end{methoddesc}
-
-\begin{methoddesc}[poll]{unregister}{fd}
-Remove a file descriptor being tracked by a polling object. Just like
-the \method{register()} method, \var{fd} can be an integer or an
-object with a \method{fileno()} method that returns an integer.
-
-Attempting to remove a file descriptor that was never registered
-causes a \exception{KeyError} exception to be raised.
-\end{methoddesc}
-
-\begin{methoddesc}[poll]{poll}{\optional{timeout}}
-Polls the set of registered file descriptors, and returns a
-possibly-empty list containing \code{(\var{fd}, \var{event})} 2-tuples
-for the descriptors that have events or errors to report.
-\var{fd} is the file descriptor, and \var{event} is a bitmask
-with bits set for the reported events for that descriptor
---- \constant{POLLIN} for waiting input,
-\constant{POLLOUT} to indicate that the descriptor can be written to, and
-so forth.
-An empty list indicates that the call timed out and no file
-descriptors had any events to report.
-If \var{timeout} is given, it specifies the length of time in
-milliseconds which the system will wait for events before returning.
-If \var{timeout} is omitted, negative, or \constant{None}, the call will
-block until there is an event for this poll object.
-\end{methoddesc}