X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/6be663cf0d9c0ce48dea6c1c2f628ed376f128c0..b6b85bdccb56b9eb8d4e5ebce4dc3ff776fc9ce8:/docs/latex/wx/file.tex

diff --git a/docs/latex/wx/file.tex b/docs/latex/wx/file.tex
index 62aedec322..3c73676200 100644
--- a/docs/latex/wx/file.tex
+++ b/docs/latex/wx/file.tex
@@ -3,17 +3,23 @@
 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{Include files}
+
+<wx/file.h>
+
 \wxheading{Constants}
 
 wx/file.h defines the following constants:
 
-{\small
 \begin{verbatim}
 #define wxS_IRUSR 00400
 #define wxS_IWUSR 00200
@@ -30,13 +36,12 @@ 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}
-}
 
 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
+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}
@@ -47,7 +52,8 @@ 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.}
 \end{twocollist}
 
 Other constants defined elsewhere but used by wxFile functions are wxInvalidOffset which represents an
@@ -78,7 +84,7 @@ fail.
 
 \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}
 
@@ -94,7 +100,7 @@ Opens a file with the given file descriptor, which has already been opened.
 
 Destructor will close the file.
 
-NB: it is not virtual so you should {\it not} derive from wxFile!
+NB: it is not virtual so you should use wxFile polymorphically.
 
 \membersection{wxFile::Access}\label{wxfileaccess}
 
@@ -109,7 +115,7 @@ values of wxFile::read or wxFile::write really make sense here.
 
 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.
@@ -146,11 +152,26 @@ Returns the file descriptor associated with the file.
 
 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}}
 
-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}
 
@@ -204,7 +225,7 @@ The number of bytes read, or the symbol {\bf wxInvalidOffset} (-1) if there was
 
 \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.
 
@@ -212,7 +233,7 @@ Seeks to the specified position.
 
 \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}
 
@@ -237,11 +258,11 @@ 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
-error occured.
+error occurred.
 
 \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.
 
@@ -253,11 +274,209 @@ Writes the specified number of bytes from a buffer.
 
 \wxheading{Return value}
 
-TRUE if the operation was successful.
+the number of bytes actually written
 
 \membersection{wxFile::Write}\label{wxfilewrites}
 
-\func{bool}{Write}{\param{const wxString& }{s}}
+\func{bool}{Write}{\param{const wxString\& }{s}}
+
+Writes the contents of the string to the file, returns TRUE on success.
+
+\section{\class{wxFFile}}\label{wxffile}
+
+wxFFile implements buffered 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. It wraps inside it a {\tt FILE *} handle used
+by standard C IO library (also known as {\tt stdio}).
+
+\wxheading{Derived from}
+
+None.
+
+\wxheading{Include files}
+
+<wx/ffile.h>
+
+\twocolwidtha{7cm}
+\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)}
+\end{twocollist}
+
+\latexignore{\rtfignore{\wxheading{Members}}}
+
+\membersection{wxFFile::wxFFile}\label{wxffileconstr}
+
+\func{}{wxFFile}{\void}
+
+Default constructor.
+
+\func{}{wxFFile}{\param{const char*}{ filename}, \param{const char*}{ mode = "r"}}
+
+Opens a file with the given mode. As there is no way to return whether the
+operation was successful or not from the constructor you should test the
+return value of \helpref{IsOpened}{wxffileisopened} to check that it didn't
+fail.
+
+\func{}{wxFFile}{\param{FILE*}{ fp}}
+
+Opens a file with the given file pointer, which has already been opened.
+
+\wxheading{Parameters}
+
+\docparam{filename}{The filename.}
+
+\docparam{mode}{The mode in which to open the file using standard C strings.
+Note that you should use {\tt "b"} flag if you use binary files under Windows
+or the results might be unexpected due to automatic newline conversion done
+for the text files.}
+
+\docparam{fp}{An existing file descriptor, such as stderr.}
+
+\membersection{wxFFile::\destruct{wxFFile}}
+
+\func{}{\destruct{wxFFile}}{\void}
+
+Destructor will close the file.
+
+NB: it is not virtual so you should {\it not} derive from wxFFile!
+
+\membersection{wxFFile::Attach}\label{wxffileattach}
+
+\func{void}{Attach}{\param{FILE*}{ fp}}
+
+Attaches an existing file pointer to the wxFFile object.
+
+The descriptor should be already opened and it will be closed by wxFFile
+object.
+
+\membersection{wxFFile::Close}\label{wxffileclose}
+
+\func{bool}{Close}{\void}
+
+Closes the file and returns TRUE on success.
+
+\membersection{wxFFile::Detach}\label{wxffiledetach}
+
+\func{void}{Detach}{\void}
+
+Get back a file pointer from wxFFile object - the caller is responsible for closing the file if this
+descriptor is opened. \helpref{IsOpened()}{wxffileisopened} will return FALSE after call to Detach().
+
+\membersection{wxFFile::fp}\label{wxffilefp}
+
+\constfunc{FILE *}{fp}{\void}
+
+Returns the file pointer associated with the file.
+
+\membersection{wxFFile::Eof}\label{wxffileeof}
+
+\constfunc{bool}{Eof}{\void}
+
+Returns TRUE if the an attempt has been made to read {\it past}
+the end of the file. 
+
+Note that the behaviour of the file descriptor based class
+\helpref{wxFile}{wxfile} is different as \helpref{wxFile::Eof}{wxfileeof}
+will return TRUE here as soon as the last byte of the file has been
+read.
+
+\membersection{wxFFile::Flush}\label{wxffileflush}
+
+\func{bool}{Flush}{\void}
+
+Flushes the file and returns TRUE on success.
+
+\membersection{wxFFile::IsOpened}\label{wxffileisopened}
+
+\constfunc{bool}{IsOpened}{\void}
+
+Returns TRUE if the file has been opened.
+
+\membersection{wxFFile::Length}\label{wxffilelength}
+
+\constfunc{size\_t}{Length}{\void}
+
+Returns the length of the file.
+
+\membersection{wxFFile::Open}\label{wxffileopen}
+
+\func{bool}{Open}{\param{const char*}{ filename}, \param{const char*}{ mode = "r"}}
+
+Opens the file, returning TRUE if successful.
+
+\wxheading{Parameters}
+
+\docparam{filename}{The filename.}
+
+\docparam{mode}{The mode in which to open the file.}
+
+\membersection{wxFFile::Read}\label{wxffileread}
+
+\func{size\_t}{Read}{\param{void*}{ buffer}, \param{off\_t}{ count}}
+
+Reads the specified number of bytes into a buffer, returning the actual number read.
+
+\wxheading{Parameters}
+
+\docparam{buffer}{A buffer to receive the data.}
+
+\docparam{count}{The number of bytes to read.}
+
+\wxheading{Return value}
+
+The number of bytes read.
+
+\membersection{wxFFile::Seek}\label{wxffileseek}
+
+\func{bool}{Seek}{\param{long }{ofs}, \param{wxSeekMode }{mode = wxFromStart}}
+
+Seeks to the specified position and returs TRUE on success.
+
+\wxheading{Parameters}
+
+\docparam{ofs}{Offset to seek to.}
+
+\docparam{mode}{One of {\bf wxFromStart}, {\bf wxFromEnd}, {\bf wxFromCurrent}.}
+
+\membersection{wxFFile::SeekEnd}\label{wxffileseekend}
+
+\func{bool}{SeekEnd}{\param{long }{ofs = 0}}
+
+Moves the file pointer to the specified number of bytes before the end of the file
+and returns TRUE on success.
+
+\wxheading{Parameters}
+
+\docparam{ofs}{Number of bytes before the end of the file.}
+
+\membersection{wxFFile::Tell}\label{wxffiletell}
+
+\constfunc{size\_t}{Tell}{\void}
+
+Returns the current position.
+
+\membersection{wxFFile::Write}\label{wxffilewrite}
+
+\func{size\_t}{Write}{\param{const void*}{ buffer}, \param{size\_t}{ count}}
+
+Writes the specified number of bytes from a buffer.
+
+\wxheading{Parameters}
+
+\docparam{buffer}{A buffer containing the data.}
+
+\docparam{count}{The number of bytes to write.}
+
+\wxheading{Return value}
+
+Number of bytes written.
+
+\membersection{wxFFile::Write}\label{wxffilewrites}
+
+\func{bool}{Write}{\param{const wxString\& }{s}}
 
 Writes the contents of the string to the file, returns TRUE on success.