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1 %//////////////////////////////////////////////////////////////////////////////
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2 %
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3 % Copyright (c) 2007,2013 Daniel Adler <dadler@uni-goettingen.de>,
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4 % Tassilo Philipp <tphilipp@potion-studios.com>
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5 %
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6 % Permission to use, copy, modify, and distribute this software for any
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7 % purpose with or without fee is hereby granted, provided that the above
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8 % copyright notice and this permission notice appear in all copies.
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9 %
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10 % THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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11 % WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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12 % MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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13 % ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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14 % WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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15 % ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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16 % OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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17 %
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18 %//////////////////////////////////////////////////////////////////////////////
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19
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20 \section{\emph{Dyncallback} C library API}
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21
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22 See the dyncallback(3) manpage for more information.
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23
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24 %@@@ removed, as manpages are more precise and up to date ------------------->
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25 %
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26 %This library extends \product{dyncall} with function callback support, allowing
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27 %the user to dynamically create a callback object that can be called directly,
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28 %or passed to functions expecting a function-pointer as argument.\\
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29 %\\
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30 %Invoking a \product{dyncallback} calls into a user-defined unified handler that
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31 %permits iteration and thus dynamic handling over the called-back-function's
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32 %parameters.\\
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33 %\\
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34 %The flexibility is constrained by the set of supported types, though.\\
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35 %\\
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36 %For style conventions and supported types, see \product{dyncall} API section.
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37 %In order to use \product{dyncallback}, include {\tt "dyncall\_callback.h"}.
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38 %
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39 %\subsection{Callback Object}
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40 %
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41 %The \emph{Callback Object} is the core component to this library.
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42 %
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43 %\paragraph{Types}
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44 %
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45 %\begin{lstlisting}[language=c]
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46 %typedef struct DCCallback DCCallback;
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47 %\end{lstlisting}
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48 %
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49 %\paragraph{Details}
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50 %The \emph{Callback Object} is an object that mimics a fully typed function
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51 %call to another function (a generic callback handler, in this case).\\
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52 %\\
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53 %This means, a pointer to this object is passed to a function accepting a pointer
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54 %to a callback function \emph{as the very callback function pointer itself}.
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55 %Or, if called directly, cast a pointer to this object to a function pointer and
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56 %issue a call.
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57 %
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58 %
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59 %\subsection{Allocation}
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60 %
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61 %\paragraph{Functions}
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62 %
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63 %\begin{lstlisting}[language=c]
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64 %DCCallback* dcbNewCallback(const DCsigchar* signature,
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65 % DCCallbackHandler* funcptr,
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66 % void* userdata,
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67 % DCaggr** aggrs);
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68 %void dcbFreeCallback(DCCallback* pcb);
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69 %\end{lstlisting}
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70 %
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71 %\lstinline{dcbNewCallback} creates and initializes a new \emph{Callback} object,
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72 %where \lstinline{signature} is the needed function signature (format is the
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73 %one outlined in the language bindings-section of this manual, see Table \ref{sigchar})
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74 %of the function to mimic, \lstinline{funcptr} is a pointer to a callback handler,
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75 %and \lstinline{userdata} a pointer to custom data that might be useful in the
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76 %handler.
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77 %Use \lstinline{dcbFreeCallback} to destroy the \emph{Callback} object.\\
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78 %\\
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79 %As with \capi{dcNewCallVM}/\capi{dcFree}, this will allocate memory using the
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80 %system allocators or custom overrides.
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81 %
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82 %
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83 %\subsection{Callback handler}
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84 %
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85 %The unified callback handler's declaration used when creating a \capi{DCCallback}
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86 %is:
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87 %
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88 %\begin{lstlisting}
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89 %DCsigchar cbHandler(DCCallback* cb,
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90 % DCArgs* args,
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91 % DCValue* result,
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92 % void* userdata);
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93 %\end{lstlisting}
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94 %
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95 %\capi{cb} is a pointer to the \capi{DCCallback} object in use, \capi{args} allows
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96 %for dynamic iteration over the called-back-function's arguments (input) and
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97 %\capi{result} is a pointer to a \capi{DCValue} object in order to store the
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98 %callback's return value (output, to be set by handler).\\
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99 %Finally, \capi{userdata} is a pointer to some user defined data that can be
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100 %set when creating the callback object.
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101 %The handler itself returns a signature character (see Table \ref{sigchar}) specifying the
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102 %data type used for \capi{result}.
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103 %
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