docs/latex/wx/ffile.tex

   1 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   2 %% Name:        ffile.tex
   3 %% Purpose:     wxFFile documentation
   4 %% Author:      Vadim Zeitlin
   5 %% Modified by:
   6 %% Created:     14.01.02 (extracted from file.tex)
   7 %% RCS-ID:      $Id$
   8 %% Copyright:   (c) Vadim Zeitlin
   9 %% License:     wxWindows license
  10 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  11
  12 \section{\class{wxFFile}}\label{wxffile}
  13
  14 wxFFile implements buffered file I/O. This is a very small class designed to
  15 minimize the overhead of using it - in fact, there is hardly any overhead at
  16 all, but using it brings you automatic error checking and hides differences
  17 between platforms and compilers. It wraps inside it a {\tt FILE *} handle used
  18 by standard C IO library (also known as {\tt stdio}).
  19
  20 \wxheading{Derived from}
  21
  22 None.
  23
  24 \wxheading{Include files}
  25
  26 <wx/ffile.h>
  27
  28 \twocolwidtha{7cm}
  29 \begin{twocollist}\itemsep=0pt%
  30 \twocolitem{{\bf wxFromStart}}{Count offset from the start of the file}
  31 \twocolitem{{\bf wxFromCurrent}}{Count offset from the current position of the file pointer}
  32 \twocolitem{{\bf wxFromEnd}}{Count offset from the end of the file (backwards)}
  33 \end{twocollist}
  34
  35 \latexignore{\rtfignore{\wxheading{Members}}}
  36
  37
  38 \membersection{wxFFile::wxFFile}\label{wxffileconstr}
  39
  40 \func{}{wxFFile}{\void}
  41
  42 Default constructor.
  43
  44 \func{}{wxFFile}{\param{const char*}{ filename}, \param{const char*}{ mode = "r"}}
  45
  46 Opens a file with the given mode. As there is no way to return whether the
  47 operation was successful or not from the constructor you should test the
  48 return value of \helpref{IsOpened}{wxffileisopened} to check that it didn't
  49 fail.
  50
  51 \func{}{wxFFile}{\param{FILE*}{ fp}}
  52
  53 Opens a file with the given file pointer, which has already been opened.
  54
  55 \wxheading{Parameters}
  56
  57 \docparam{filename}{The filename.}
  58
  59 \docparam{mode}{The mode in which to open the file using standard C strings.
  60 Note that you should use {\tt "b"} flag if you use binary files under Windows
  61 or the results might be unexpected due to automatic newline conversion done
  62 for the text files.}
  63
  64 \docparam{fp}{An existing file descriptor, such as stderr.}
  65
  66
  67 \membersection{wxFFile::\destruct{wxFFile}}
  68
  69 \func{}{\destruct{wxFFile}}{\void}
  70
  71 Destructor will close the file.
  72
  73 NB: it is not virtual so you should {\it not} derive from wxFFile!
  74
  75
  76 \membersection{wxFFile::Attach}\label{wxffileattach}
  77
  78 \func{void}{Attach}{\param{FILE*}{ fp}}
  79
  80 Attaches an existing file pointer to the wxFFile object.
  81
  82 The descriptor should be already opened and it will be closed by wxFFile
  83 object.
  84
  85
  86 \membersection{wxFFile::Close}\label{wxffileclose}
  87
  88 \func{bool}{Close}{\void}
  89
  90 Closes the file and returns \true on success.
  91
  92
  93 \membersection{wxFFile::Detach}\label{wxffiledetach}
  94
  95 \func{void}{Detach}{\void}
  96
  97 Get back a file pointer from wxFFile object -- the caller is responsible for closing the file if this
  98 descriptor is opened. \helpref{IsOpened()}{wxffileisopened} will return \false after call to Detach().
  99
 100
 101 \membersection{wxFFile::fp}\label{wxffilefp}
 102
 103 \constfunc{FILE *}{fp}{\void}
 104
 105 Returns the file pointer associated with the file.
 106
 107
 108 \membersection{wxFFile::Eof}\label{wxffileeof}
 109
 110 \constfunc{bool}{Eof}{\void}
 111
 112 Returns \true if the an attempt has been made to read {\it past}
 113 the end of the file.
 114
 115 Note that the behaviour of the file descriptor based class
 116 \helpref{wxFile}{wxfile} is different as \helpref{wxFile::Eof}{wxfileeof}
 117 will return \true here as soon as the last byte of the file has been
 118 read.
 119
 120 Also note that this method may only be called for opened files and may crash if
 121 the file is not opened.
 122
 123 \wxheading{See also}
 124
 125 \helpref{IsOpened}{wxffileisopened}
 126
 127
 128 \membersection{wxFFile::Error}\label{wxffileerror}
 129
 130 Returns \true if an error has occured on this file, similar to the standard
 131 \texttt{ferror()} function.
 132
 133 Please note that this method may only be called for opened files and may crash
 134 if the file is not opened.
 135
 136 \wxheading{See also}
 137
 138 \helpref{IsOpened}{wxffileisopened}
 139
 140
 141 \membersection{wxFFile::Flush}\label{wxffileflush}
 142
 143 \func{bool}{Flush}{\void}
 144
 145 Flushes the file and returns \true on success.
 146
 147
 148 \membersection{wxFFile::IsOpened}\label{wxffileisopened}
 149
 150 \constfunc{bool}{IsOpened}{\void}
 151
 152 Returns \true if the file is opened. Most of the methods of this class may only
 153 be used for an opened file.
 154
 155
 156 \membersection{wxFFile::Length}\label{wxffilelength}
 157
 158 \constfunc{size\_t}{Length}{\void}
 159
 160 Returns the length of the file.
 161
 162
 163 \membersection{wxFFile::Open}\label{wxffileopen}
 164
 165 \func{bool}{Open}{\param{const char*}{ filename}, \param{const char*}{ mode = "r"}}
 166
 167 Opens the file, returning \true if successful.
 168
 169 \wxheading{Parameters}
 170
 171 \docparam{filename}{The filename.}
 172
 173 \docparam{mode}{The mode in which to open the file.}
 174
 175
 176 \membersection{wxFFile::Read}\label{wxffileread}
 177
 178 \func{size\_t}{Read}{\param{void*}{ buffer}, \param{off\_t}{ count}}
 179
 180 Reads the specified number of bytes into a buffer, returning the actual number read.
 181
 182 \wxheading{Parameters}
 183
 184 \docparam{buffer}{A buffer to receive the data.}
 185
 186 \docparam{count}{The number of bytes to read.}
 187
 188 \wxheading{Return value}
 189
 190 The number of bytes read.
 191
 192
 193 \membersection{wxFFile::Seek}\label{wxffileseek}
 194
 195 \func{bool}{Seek}{\param{long }{ofs}, \param{wxSeekMode }{mode = wxFromStart}}
 196
 197 Seeks to the specified position and returns \true on success.
 198
 199 \wxheading{Parameters}
 200
 201 \docparam{ofs}{Offset to seek to.}
 202
 203 \docparam{mode}{One of {\bf wxFromStart}, {\bf wxFromEnd}, {\bf wxFromCurrent}.}
 204
 205
 206 \membersection{wxFFile::SeekEnd}\label{wxffileseekend}
 207
 208 \func{bool}{SeekEnd}{\param{long }{ofs = 0}}
 209
 210 Moves the file pointer to the specified number of bytes before the end of the file
 211 and returns \true on success.
 212
 213 \wxheading{Parameters}
 214
 215 \docparam{ofs}{Number of bytes before the end of the file.}
 216
 217
 218 \membersection{wxFFile::Tell}\label{wxffiletell}
 219
 220 \constfunc{size\_t}{Tell}{\void}
 221
 222 Returns the current position.
 223
 224
 225 \membersection{wxFFile::Write}\label{wxffilewrite}
 226
 227 \func{size\_t}{Write}{\param{const void*}{ buffer}, \param{size\_t}{ count}}
 228
 229 Writes the specified number of bytes from a buffer.
 230
 231 \wxheading{Parameters}
 232
 233 \docparam{buffer}{A buffer containing the data.}
 234
 235 \docparam{count}{The number of bytes to write.}
 236
 237 \wxheading{Return value}
 238
 239 Number of bytes written.
 240
 241
 242 \membersection{wxFFile::Write}\label{wxffilewrites}
 243
 244 \func{bool}{Write}{\param{const wxString\& }{s}, \param{wxMBConv\&}{ conv = wxConvUTF8}}
 245
 246 Writes the contents of the string to the file, returns \true on success.
 247
 248 The second argument is only meaningful in Unicode build of wxWindows when
 249 {\it conv} is used to convert {\it s} to multibyte representation.
 250
 251