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Document new file() constructor, with the body of open()'s text, plus a 

"new in 2.2" blurb at the end.  Replace open()'s text by pointing back
to file().
This commit is contained in:
Tim Peters 2001-09-20 19:55:29 +00:00
parent f47d8ef683
commit 2e29bfbe1a
1 changed files with 45 additions and 37 deletions
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80
Doc/lib/libfuncs.tex
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@ -252,6 +252,49 @@ class instances are callable if they have a \method{__call__()} method.
\code{None}.
\end{funcdesc}
\begin{funcdesc}{file}{filename\optional{, mode\optional{, bufsize}}}
Return a new file object (described earlier under Built-in Types).
The first two arguments are the same as for \code{stdio}'s
\cfunction{fopen()}: \var{filename} is the file name to be opened,
\var{mode} indicates how the file is to be opened: \code{'r'} for
reading, \code{'w'} for writing (truncating an existing file), and
\code{'a'} opens it for appending (which on \emph{some} \UNIX{}
systems means that \emph{all} writes append to the end of the file,
regardless of the current seek position).
Modes \code{'r+'}, \code{'w+'} and \code{'a+'} open the file for
updating (note that \code{'w+'} truncates the file). Append
\code{'b'} to the mode to open the file in binary mode, on systems
that differentiate between binary and text files (else it is
ignored). If the file cannot be opened, \exception{IOError} is
raised.
If \var{mode} is omitted, it defaults to \code{'r'}. When opening a
binary file, you should append \code{'b'} to the \var{mode} value
for improved portability. (It's useful even on systems which don't
treat binary and text files differently, where it serves as
documentation.)
\index{line-buffered I/O}\index{unbuffered I/O}\index{buffer size, I/O}
\index{I/O control!buffering}
The optional \var{bufsize} argument specifies the
file's desired buffer size: 0 means unbuffered, 1 means line
buffered, any other positive value means use a buffer of
(approximately) that size. A negative \var{bufsize} means to use
the system default, which is usually line buffered for for tty
devices and fully buffered for other files. If omitted, the system
default is used.\footnote{
Specifying a buffer size currently has no effect on systems that
don't have \cfunction{setvbuf()}. The interface to specify the
buffer size is not done using a method that calls
\cfunction{setvbuf()}, because that may dump core when called
after any I/O has been performed, and there's no reliable way to
determine whether this is the case.}
The \function{file()} constructor is new in Python 2.2. The previous
spelling, \function{open()}, is retained for compatibility, and is an
alias for \function{file()}.
\end{funcdesc}
\begin{funcdesc}{filter}{function, list}
Construct a list from those elements of \var{list} for which
\var{function} returns true. \var{list} may be either a sequence, a
@ -479,42 +522,7 @@ the interpreter.
\end{funcdesc}
\begin{funcdesc}{open}{filename\optional{, mode\optional{, bufsize}}}
Return a new file object (described earlier under Built-in Types).
The first two arguments are the same as for \code{stdio}'s
\cfunction{fopen()}: \var{filename} is the file name to be opened,
\var{mode} indicates how the file is to be opened: \code{'r'} for
reading, \code{'w'} for writing (truncating an existing file), and
\code{'a'} opens it for appending (which on \emph{some} \UNIX{}
systems means that \emph{all} writes append to the end of the file,
regardless of the current seek position).
Modes \code{'r+'}, \code{'w+'} and \code{'a+'} open the file for
updating (note that \code{'w+'} truncates the file). Append
\code{'b'} to the mode to open the file in binary mode, on systems
that differentiate between binary and text files (else it is
ignored). If the file cannot be opened, \exception{IOError} is
raised.
If \var{mode} is omitted, it defaults to \code{'r'}. When opening a
binary file, you should append \code{'b'} to the \var{mode} value
for improved portability. (It's useful even on systems which don't
treat binary and text files differently, where it serves as
documentation.)
\index{line-buffered I/O}\index{unbuffered I/O}\index{buffer size, I/O}
\index{I/O control!buffering}
The optional \var{bufsize} argument specifies the
file's desired buffer size: 0 means unbuffered, 1 means line
buffered, any other positive value means use a buffer of
(approximately) that size. A negative \var{bufsize} means to use
the system default, which is usually line buffered for for tty
devices and fully buffered for other files. If omitted, the system
default is used.\footnote{
Specifying a buffer size currently has no effect on systems that
don't have \cfunction{setvbuf()}. The interface to specify the
buffer size is not done using a method that calls
\cfunction{setvbuf()}, because that may dump core when called
after any I/O has been performed, and there's no reliable way to
determine whether this is the case.}
An alias for the \function{file()} function above.
\end{funcdesc}
\begin{funcdesc}{ord}{c}