changed wxImage::ComputeHistogram to use wxHashMap

[wxWidgets.git] / docs / latex / wx / file.tex

diff --git a/docs/latex/wx/file.tex b/docs/latex/wx/file.tex
index da864d38dbe373c9542a82722cb8a5b3c9656954..4b2160def6495a961a6881bd33b4dab9ccd34239 100644 (file)
--- a/docs/latex/wx/file.tex
+++ b/docs/latex/wx/file.tex
@@ -1,18 +1,36 @@
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%% Name:        file.tex
+%% Purpose:     wxFile documentation
+%% Author:      Vadim Zeitlin
+%% Modified by:
+%% Created:     14.01.02 (extracted from file.tex)
+%% RCS-ID:      $Id$
+%% Copyright:   (c) Vadim Zeitlin
+%% License:     wxWindows license
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+

 \section{\class{wxFile}}\label{wxfile}
 
 A wxFile performs raw file I/O. This is a very small class designed to
 minimize the overhead of using it - in fact, there is hardly any overhead at
 all, but using it brings you automatic error checking and hides differences
 \section{\class{wxFile}}\label{wxfile}
 
 A wxFile performs raw file I/O. This is a very small class designed to
 minimize the overhead of using it - in fact, there is hardly any overhead at
 all, but using it brings you automatic error checking and hides differences

-between platforms and compilers.
+between platforms and compilers. wxFile also automatically closes the file in
+its destructor making it unnecessary to worry about forgetting to do it.
+wxFile is a wrapper around {\tt file descriptor.} - see also 
+\helpref{wxFFile}{wxffile} for a wrapper around {\tt FILE} structure.

 
 \wxheading{Derived from}
 
 None.
 
 
 \wxheading{Derived from}
 
 None.
 

+\wxheading{Include files}
+
+<wx/file.h>
+

 \wxheading{Constants}
 
 wx/file.h defines the following constants:
 \wxheading{Constants}
 
 wx/file.h defines the following constants:

-{\small
+

 \begin{verbatim}
 #define wxS_IRUSR 00400
 #define wxS_IWUSR 00200
 \begin{verbatim}
 #define wxS_IRUSR 00400
 #define wxS_IWUSR 00200


@@ -29,25 +47,26 @@ wx/file.h defines the following constants:
 // default mode for the new files: corresponds to umask 022
 #define wxS_DEFAULT  (wxS_IRUSR | wxS_IWUSR | wxS_IRGRP | wxS_IWGRP | wxS_IROTH | wxS_IWOTH)
 \end{verbatim}
 // default mode for the new files: corresponds to umask 022
 #define wxS_DEFAULT  (wxS_IRUSR | wxS_IWUSR | wxS_IRGRP | wxS_IWGRP | wxS_IROTH | wxS_IWOTH)
 \end{verbatim}

-}

 
 These constants define the file access rights and are used with 
 \helpref{wxFile::Create}{wxfilecreate} and \helpref{wxFile::Open}{wxfileopen}.
 
 The {\it OpenMode} enumeration defines the different modes for opening a file,
 
 These constants define the file access rights and are used with 
 \helpref{wxFile::Create}{wxfilecreate} and \helpref{wxFile::Open}{wxfileopen}.
 
 The {\it OpenMode} enumeration defines the different modes for opening a file,

-it's defined inside wxFile class so its members should be specified with {\it
-wxFile::} scope resolution prefix. It is also used with 
-\helpref{wxFile::Access}{wxfileaccess} function.
+it is defined inside wxFile class so its members should be specified with {\it wxFile::} scope
+resolution prefix. It is also used with \helpref{wxFile::Access}{wxfileaccess} function.

 
 

-\twocolwidtha{7cm}%
-\begin{twocollist}\itemsep=0pt
+\twocolwidtha{7cm}
+\begin{twocollist}\itemsep=0pt%

 \twocolitem{{\bf wxFile::read}}{Open file for reading or test if it can be opened for reading with Access()}
 \twocolitem{{\bf wxFile::write}}{Open file for writing deleting the contents of the file if it already exists
 or test if it can be opened for writing with Access()}
 \twocolitem{{\bf wxFile::read\_write}}{Open file for reading and writing; can not be used with Access()}
 \twocolitem{{\bf wxFile::write\_append}}{Open file for appending: the file is opened for writing, but the old
 contents of the file is not erased and the file pointer is initially placed at the end of the file;
 \twocolitem{{\bf wxFile::read}}{Open file for reading or test if it can be opened for reading with Access()}
 \twocolitem{{\bf wxFile::write}}{Open file for writing deleting the contents of the file if it already exists
 or test if it can be opened for writing with Access()}
 \twocolitem{{\bf wxFile::read\_write}}{Open file for reading and writing; can not be used with Access()}
 \twocolitem{{\bf wxFile::write\_append}}{Open file for appending: the file is opened for writing, but the old
 contents of the file is not erased and the file pointer is initially placed at the end of the file;

-can not be used with Access()}
+can not be used with Access(). This is the same as {\bf wxFile::write} if the
+file doesn't exist.}
+\twocolitem{{\bf wxFile::write\_excl}}{Open the file securely for writing (Uses O\_EXCL | O\_CREAT).
+Will fail if the file already exists, else create and open it atomically.  Useful for opening temporary files without being vulnerable to race exploits.}

 \end{twocollist}
 
 Other constants defined elsewhere but used by wxFile functions are wxInvalidOffset which represents an
 \end{twocollist}
 
 Other constants defined elsewhere but used by wxFile functions are wxInvalidOffset which represents an


@@ -55,7 +74,7 @@ invalid value of type {\it off\_t} and is returned by functions returning {\it o
 mode constants used with \helpref{Seek()}{wxfileseek}:
 
 \twocolwidtha{7cm}
 mode constants used with \helpref{Seek()}{wxfileseek}:
 
 \twocolwidtha{7cm}

-\begin{twocollist}\itemsep=0pt
+\begin{twocollist}\itemsep=0pt%

 \twocolitem{{\bf wxFromStart}}{Count offset from the start of the file}
 \twocolitem{{\bf wxFromCurrent}}{Count offset from the current position of the file pointer}
 \twocolitem{{\bf wxFromEnd}}{Count offset from the end of the file (backwards)}
 \twocolitem{{\bf wxFromStart}}{Count offset from the start of the file}
 \twocolitem{{\bf wxFromCurrent}}{Count offset from the current position of the file pointer}
 \twocolitem{{\bf wxFromEnd}}{Count offset from the end of the file (backwards)}


@@ -78,7 +97,7 @@ fail.
 
 \func{}{wxFile}{\param{int}{ fd}}
 
 
 \func{}{wxFile}{\param{int}{ fd}}
 

-Opens a file with the given file descriptor, which has already been opened.
+Associates the file with the given file descriptor, which has already been opened.

 
 \wxheading{Parameters}
 
 
 \wxheading{Parameters}
 


@@ -94,20 +113,22 @@ Opens a file with the given file descriptor, which has already been opened.
 
 Destructor will close the file.
 
 
 Destructor will close the file.
 

-NB: it is not virtual so you should {\it not} derive from wxFile!
+{\bf NB:} it is not virtual so you should not use wxFile polymorphically.

 
 \membersection{wxFile::Access}\label{wxfileaccess}
 
 \membersection{wxFile::Access}\label{wxfileaccess}

-\func{static bool}{Access}{\param{const char *}{ name}, \param{OpenMode}{ mode}
+
+\func{static bool}{Access}{\param{const char *}{ name}, \param{OpenMode}{ mode}}

 
 This function verifies if we may access the given file in specified mode. Only
 values of wxFile::read or wxFile::write really make sense here.
 
 \membersection{wxFile::Attach}\label{wxfileattach}
 
 This function verifies if we may access the given file in specified mode. Only
 values of wxFile::read or wxFile::write really make sense here.
 
 \membersection{wxFile::Attach}\label{wxfileattach}

+

 \func{void}{Attach}{\param{int}{ fd}}
 
 Attaches an existing file descriptor to the wxFile object. Example of predefined
 file descriptors are 0, 1 and 2 which correspond to stdin, stdout and stderr (and
 \func{void}{Attach}{\param{int}{ fd}}
 
 Attaches an existing file descriptor to the wxFile object. Example of predefined
 file descriptors are 0, 1 and 2 which correspond to stdin, stdout and stderr (and

-have symbolic names of wxFile::fd\_stdin, wxFile::fd\_stdout and wxFile::fd\_stderr).
+have symbolic names of {\bf wxFile::fd\_stdin}, {\bf wxFile::fd\_stdout} and {\bf wxFile::fd\_stderr}).

 
 The descriptor should be already opened and it will be closed by wxFile
 object.
 
 The descriptor should be already opened and it will be closed by wxFile
 object.


@@ -126,12 +147,14 @@ Creates a file for writing. If the file already exists, setting {\bf overwrite}
 will ensure it is overwritten.
 
 \membersection{wxFile::Detach}\label{wxfiledetach}
 will ensure it is overwritten.
 
 \membersection{wxFile::Detach}\label{wxfiledetach}

+

 \func{void}{Detach}{\void}
 
 Get back a file descriptor from wxFile object - the caller is responsible for closing the file if this
 descriptor is opened. \helpref{IsOpened()}{wxfileisopened} will return FALSE after call to Detach().
 
 \membersection{wxFile::fd}\label{wxfilefd}
 \func{void}{Detach}{\void}
 
 Get back a file descriptor from wxFile object - the caller is responsible for closing the file if this
 descriptor is opened. \helpref{IsOpened()}{wxfileisopened} will return FALSE after call to Detach().
 
 \membersection{wxFile::fd}\label{wxfilefd}

+

 \constfunc{int}{fd}{\void}
 
 Returns the file descriptor associated with the file.
 \constfunc{int}{fd}{\void}
 
 Returns the file descriptor associated with the file.


@@ -142,11 +165,26 @@ Returns the file descriptor associated with the file.
 
 Returns TRUE if the end of the file has been reached.
 
 
 Returns TRUE if the end of the file has been reached.
 

+Note that the behaviour of the file pointer based class 
+\helpref{wxFFile}{wxffile} is different as \helpref{wxFFile::Eof}{wxffileeof} 
+will return TRUE here only if an attempt has been made to read 
+{\it past} the last byte of the file, while wxFile::Eof() will return TRUE
+even before such attempt is made if the file pointer is at the last position
+in the file.
+
+Note also that this function doesn't work on unseekable file descriptors
+(examples include pipes, terminals and sockets under Unix) and an attempt to
+use it will result in an error message in such case. So, to read the entire
+file into memory, you should write a loop which uses 
+\helpref{Read}{wxfileread} repeatedly and tests its return condition instead
+of using Eof() as this will not work for special files under Unix.
+

 \membersection{wxFile::Exists}\label{wxfileexists}
 
 \func{static bool}{Exists}{\param{const char*}{ filename}}
 
 \membersection{wxFile::Exists}\label{wxfileexists}
 
 \func{static bool}{Exists}{\param{const char*}{ filename}}
 

-Returns TRUE if the given name specifies an existing regular file.
+Returns TRUE if the given name specifies an existing regular file (not a
+directory or a link)

 
 \membersection{wxFile::Flush}\label{wxfileflush}
 
 
 \membersection{wxFile::Flush}\label{wxfileflush}
 


@@ -200,7 +238,7 @@ The number of bytes read, or the symbol {\bf wxInvalidOffset} (-1) if there was
 
 \membersection{wxFile::Seek}\label{wxfileseek}
 
 
 \membersection{wxFile::Seek}\label{wxfileseek}
 

-\func{off\_t}{Seek}{\param{off\_t }{ofs}, \param{wxFile::SeekMode }{mode = wxFile::FromStart}}
+\func{off\_t}{Seek}{\param{off\_t }{ofs}, \param{wxSeekMode }{mode = wxFromStart}}

 
 Seeks to the specified position.
 
 
 Seeks to the specified position.
 


@@ -208,7 +246,7 @@ Seeks to the specified position.
 
 \docparam{ofs}{Offset to seek to.}
 
 
 \docparam{ofs}{Offset to seek to.}
 

-\docparam{mode}{One of {\bf wxFile::FromStart}, {\bf wxFile::FromEnd}, {\bf wxFile::FromCurrent}.}
+\docparam{mode}{One of {\bf wxFromStart}, {\bf wxFromEnd}, {\bf wxFromCurrent}.}

 
 \wxheading{Return value}
 
 
 \wxheading{Return value}
 


@@ -233,11 +271,11 @@ The actual offset position achieved, or wxInvalidOffset on failure.
 \constfunc{off\_t}{Tell}{\void}
 
 Returns the current position or wxInvalidOffset if file is not opened or if another
 \constfunc{off\_t}{Tell}{\void}
 
 Returns the current position or wxInvalidOffset if file is not opened or if another

-error occured.
+error occurred.

 
 \membersection{wxFile::Write}\label{wxfilewrite}
 
 
 \membersection{wxFile::Write}\label{wxfilewrite}
 

-\func{bool}{Write}{\param{const void*}{ buffer}, \param{off\_t}{ count}}
+\func{size\_t}{Write}{\param{const void*}{ buffer}, \param{off\_t}{ count}}

 
 Writes the specified number of bytes from a buffer.
 
 
 Writes the specified number of bytes from a buffer.
 


@@ -249,9 +287,14 @@ Writes the specified number of bytes from a buffer.
 
 \wxheading{Return value}
 
 
 \wxheading{Return value}
 

-TRUE if the operation was successful.
+the number of bytes actually written

 
 \membersection{wxFile::Write}\label{wxfilewrites}
 
 \membersection{wxFile::Write}\label{wxfilewrites}

-\func{bool}{Write}{\param{const wxString& }{s}}

 
 

-Writes the contents of the string to the file, returns TRUE on success
+\func{bool}{Write}{\param{const wxString\& }{s}, \param{wxMBConv&}{ conv = wxConvLibc}}
+
+Writes the contents of the string to the file, returns TRUE on success.
+
+The second argument is only meaningful in Unicode build of wxWindows when
+{\it conv} is used to convert {\it s} to multibyte representation.
+