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Diff for /gforth/doc/gforth.ds between versions 1.179 and 1.180

version 1.179, 2007/06/01 18:41:07 version 1.180, 2007/06/09 15:55:44
Line 406  C Interface Line 406  C Interface
   
 * Calling C Functions::           * Calling C Functions::         
 * Declaring C Functions::         * Declaring C Functions::       
   * Calling C function pointers::  
 * Callbacks::                     * Callbacks::                   
 * C interface internals::         * C interface internals::       
 * Low-Level C Interface Words::    * Low-Level C Interface Words::  
Line 11835  as well as a way of declaring structs, u Line 11836  as well as a way of declaring structs, u
 @menu  @menu
 * Calling C Functions::           * Calling C Functions::         
 * Declaring C Functions::         * Declaring C Functions::       
   * Calling C function pointers::  
 * Callbacks::                     * Callbacks::                   
 * C interface internals::         * C interface internals::       
 * Low-Level C Interface Words::    * Low-Level C Interface Words::  
Line 11908  calling the appropriate word for the des Line 11910  calling the appropriate word for the des
   
   
   
 @node Declaring C Functions, Callbacks, Calling C Functions, C Interface  @node Declaring C Functions, Calling C function pointers, Calling C Functions, C Interface
 @subsection Declaring C Functions  @subsection Declaring C Functions
 @cindex C functions, declarations  @cindex C functions, declarations
 @cindex declaring C functions  @cindex declaring C functions
Line 12011  interface; you can find some examples fo Line 12013  interface; you can find some examples fo
 in @file{lib.fs}.  in @file{lib.fs}.
   
   
   @node Calling C function pointers, Callbacks, Declaring C Functions, C Interface
   @subsection Calling C function pointers from Forth
   @cindex C function pointers, calling from Forth
   
   If you come across a C function pointer (e.g., in some C-constructed
   structure) and want to call it from your Forth program, you can also
   use the features explained until now to achieve that, as follows:
   
   Let us assume that there is a C function pointer type @code{func1}
   defined in some header file @file{func1.h}, and you know that these
   functions take one integer argument and return an integer result; and
   you want to call functions through such pointers.  Just define
   
 @node Callbacks, C interface internals, Declaring C Functions, C Interface  @example
   \c #include <func1.h>
   \c #define call_func1(par1,fptr) ((func1)fptr)(par1)
   c-function call-func1 call_func1 n func -- n
   @end example
   
   and then you can call a function pointed to by, say @code{func1a} as
   follows:
   
   @example
   -5 func1a call-func1 .
   @end example
   
   In the C part, @code{call_func} is defined as a macro to avoid having
   to declare the exact parameter and return types, so the C compiler
   knows them from the declaration of @code{func1}.
   
   The Forth word @code{call-func1} is similar to @code{execute}, except
   that it takes a C @code{func1} pointer instead of a Forth execution
   token, and it is specific to @code{func1} pointers.  For each type of
   function pointer you want to call from Forth, you have to define
   a separate calling word.
   
   
   @node Callbacks, C interface internals, Calling C function pointers, C Interface
 @subsection Callbacks  @subsection Callbacks
 @cindex Callback functions written in Forth  @cindex Callback functions written in Forth
 @cindex C function pointers to Forth words  @cindex C function pointers to Forth words
Removed from v.1.179  
changed lines
  Added in v.1.180

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