/////////////////////////////////////////////////////////////////////////////
// Name: file.h
-// Purpose: interface of wxTempFile
+// Purpose: interface of wxTempFile, wxFile
// Author: wxWidgets team
// RCS-ID: $Id$
-// Licence: wxWindows license
+// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
-//@{
-/**
- These constants define the file access rights and are used with wxFile::Create and wxFile::Open.
-*/
-#define wxS_IRUSR 00400
-#define wxS_IWUSR 00200
-#define wxS_IXUSR 00100
-
-#define wxS_IRGRP 00040
-#define wxS_IWGRP 00020
-#define wxS_IXGRP 00010
-
-#define wxS_IROTH 00004
-#define wxS_IWOTH 00002
-#define wxS_IXOTH 00001
-
-/** 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)
-//@}
-
-
-
/**
@class wxTempFile
file by default, you should explicitly call wxTempFile::Commit() to do it.
Calling wxTempFile::Discard() explicitly discards any modifications: it
closes and deletes the temporary file and leaves the original file unchanged.
- If you don't call neither of Commit() and Discard(), the destructor will
+ If you call neither Commit() nor Discard(), the destructor will
call Discard() automatically.
To summarize: if you want to replace another file, create an instance of
- wxTempFile passing the name of the file to be replaced to the constructor
- (you may also use default constructor and pass the file name to wxTempFile::Open).
+ wxTempFile passing the name of the file to be replaced to the constructor.
+ (You may also use default constructor and pass the file name to wxTempFile::Open.)
Then you can write to wxTempFile using wxFile-like functions and later call
wxTempFile::Commit() to replace the old file (and close this one) or call
wxTempFile::Discard() to cancel the modifications.
public:
/**
Associates wxTempFile with the file to be replaced and opens it.
- You should use IsOpened() to verify if the constructor succeeded.
+
+ @warning
+ You should use IsOpened() to verify that the constructor succeeded.
*/
wxTempFile(const wxString& strName);
/**
- Destructor calls Discard() if temporary file is still opened.
+ Destructor calls Discard() if temporary file is still open.
*/
~wxTempFile();
file to the old name. Returns @true if both actions succeeded.
If @false is returned it may unfortunately mean two quite different things:
- either that either the old file couldn't be deleted or that the new file
+ either that the old file couldn't be deleted or that the new file
couldn't be renamed to the old name.
*/
bool Commit();
/**
- Discard changes: the old file contents is not changed, temporary file is
- deleted.
+ Discard changes: the old file contents are not changed, the temporary
+ file is deleted.
*/
void Discard();
+ /**
+ Flush the data written to the file to disk.
+
+ This simply calls wxFile::Flush() for the underlying file and may be
+ necessary with file systems such as XFS and Ext4 under Linux. Calling
+ this function may however have serious performance implications and
+ also is not necessary with many other file systems so it is not done by
+ default -- but you can call it before calling Commit() to absolutely
+ ensure that the data was indeed written to the disk correctly.
+ */
+ bool Flush();
+
/**
Returns @true if the file was successfully opened.
*/
/**
Returns the length of the file.
- This method may return wxInvalidOffset if the length couldn't be
- determined or also 0 even for non-empty files if the file is not
- seekable.
+ This method may return ::wxInvalidOffset if the length couldn't be
+ determined or 0 even for non-empty files if the file is not seekable.
In general, the only way to determine if the file for which this function
returns 0 is really empty or not is to try reading from it.
wxSeekMode mode = wxFromStart);
/**
- Returns the current position or wxInvalidOffset if file is not opened or
+ Returns the current position or ::wxInvalidOffset if file is not opened or
if another error occurred.
*/
wxFileOffset Tell() const;
/**
@class 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.
-
- wxFile also automatically closes the file in its destructor making it unnecessary
- to worry about forgetting to do it.
-
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. wxFile also automatically closes the file in
- its destructor making it unnecessary to worry about forgetting to do it.
+ its destructor so you won't forget to do so.
wxFile is a wrapper around @c file descriptor. - see also wxFFile for a
wrapper around @c FILE structure.
or test if it can be opened for writing with Access(). */
write,
- /** Open file for reading and writing; can not be used with Access() */
+ /** Open file for reading and writing; cannot be used with Access() */
read_write,
/** 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().
+ of the file are not erased and the file pointer is initially placed at the end
+ of the file; cannot be used with Access().
This is the same as OpenMode::write if the file doesn't exist.
*/
The filename.
@param mode
The mode in which to open the file.
+
+ @warning
+ You should use IsOpened() to verify that the constructor succeeded.
*/
wxFile(const wxString& filename,
wxFile::OpenMode mode = wxFile::read);
/**
Destructor will close the file.
- @note it is not virtual so you should not use wxFile polymorphically.
+ @note This destructor is not virtual so you should not use wxFile polymorphically.
*/
~wxFile();
+ /**
+ Returns the error code for the last unsuccessful operation.
+
+ The error code is system-dependent and corresponds to the value of the
+ standard @c errno variable when the last error occurred.
+
+ Notice that only simple accessors such as IsOpened() and Eof() (and
+ this method itself) don't modify the last error value, all other
+ methods can potentially change it if an error occurs, including the
+ const ones such as Tell() or Length().
+
+ @since 2.9.2
+
+ @see ClearLastError()
+ */
+ int GetLastError() const;
+
+ /**
+ Resets the error code.
+
+ GetLastError() will return 0 until the next error occurs.
+
+ @since 2.9.2
+ */
+ void ClearLastError();
+
/**
This function verifies if we may access the given file in specified mode.
Only values of @c wxFile::read or @c 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
+ Examples of predefined file descriptors are 0, 1 and 2 which correspond to
stdin, stdout and stderr (and have symbolic names of @c wxFile::fd_stdin,
@c wxFile::fd_stdout and @c wxFile::fd_stderr).
/**
Closes the file.
*/
- void Close();
+ bool Close();
/**
Creates a file for writing.
If the file already exists, setting @b overwrite to @true will ensure
it is overwritten.
- @a access may be an OR combination of the file access values
- like ::wxS_IRUSR, ::wxS_IWUSR, etc, etc.
+ @a access may be an OR combination of the ::wxPosixPermissions enumeration
+ values.
*/
bool Create(const wxString& filename,
bool overwrite = false,
/**
Returns @true if the end of the file has been reached.
- Note that the behaviour of the file pointer based class wxFFile is
+ Note that the behaviour of the file pointer-based class wxFFile is
different as wxFFile::Eof() will return @true here only if an
attempt has been made to read @b past the last byte of the file, while
wxFile::Eof() will return @true even before such attempt is made if the
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.
+ use it will result in an error message.
So, to read the entire file into memory, you should write a loop which uses
Read() repeatedly and tests its return condition instead of using Eof()
/**
Returns @true if the given name specifies an existing regular file
- (not a directory or a link)
+ (not a directory or a link).
*/
static bool Exists(const wxString& filename);
The filename.
@param mode
The mode in which to open the file.
+ @param access
+ An OR-combination of ::wxPosixPermissions enumeration values.
*/
- bool Open(const wxString& filename,
- wxFile::OpenMode mode = wxFile::read);
+ bool Open(const wxString& filename, wxFile::OpenMode mode = wxFile::read,
+ int access = wxS_DEFAULT);
/**
Reads from the file into a memory buffer.
@param count
Bytes to read
- @return The number of bytes read, or the symbol wxInvalidOffset.
+ @return The number of bytes read, or the symbol ::wxInvalidOffset.
*/
- size_t Read(void* buffer, size_t count);
+ ssize_t Read(void* buffer, size_t count);
/**
Seeks to the specified position.
@param mode
One of wxFromStart, wxFromEnd, wxFromCurrent.
- @return The actual offset position achieved, or wxInvalidOffset on
+ @return The actual offset position achieved, or ::wxInvalidOffset on
failure.
*/
wxFileOffset Seek(wxFileOffset ofs,
@param ofs
Number of bytes before the end of the file.
- @return The actual offset position achieved, or wxInvalidOffset on
+ @return The actual offset position achieved, or ::wxInvalidOffset on
failure.
*/
wxFileOffset SeekEnd(wxFileOffset ofs = 0);
/**
- Returns the current position or wxInvalidOffset if file is not opened or
+ Returns the current position or ::wxInvalidOffset if file is not opened or
if another error occurred.
*/
wxFileOffset Tell() const;
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