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OpenDarwin 7.2.1 - man page for tcl_getmathfuncinfo (opendarwin section 3)

Tcl_CreateMathFunc(3)		      Tcl Library Procedures		    Tcl_CreateMathFunc(3)


       Tcl_CreateMathFunc,  Tcl_GetMathFuncInfo,  Tcl_ListMathFuncs - Define, query and enumerate
       math functions for expressions

       #include <tcl.h>

       Tcl_CreateMathFunc(interp, name, numArgs, argTypes, proc, clientData)

       int											  |
       Tcl_GetMathFuncInfo(interp, name, numArgsPtr, argTypesPtr, procPtr, clientDataPtr)	  |

       Tcl_Obj *										  |
       Tcl_ListMathFuncs(interp, pattern)							  |

       Tcl_Interp      *interp		(in)	  Interpreter  in  which  new  function  will  be
						  defined.					  |

       CONST char      *name		(in)							  |
						  Name for new function.

       int	       numArgs		(in)	  Number  of  arguments  to  new  function;  also
						  gives size of argTypes array.

       Tcl_ValueType   *argTypes	(in)	  Points to an array giving the permissible types
						  for each argument to function.

       Tcl_MathProc    *proc		(in)	  Procedure that implements the function.

       ClientData      clientData	(in)	  Arbitrary  one-word  value to pass to proc when
						  it is invoked.

       int	       *numArgsPtr	(out)	  Points to a variable that will be set  to  con-
						  tain the number of arguments to the function.

       Tcl_ValueType   **argTypesPtr	(out)	  Points  to  a variable that will be set to con-
						  tain a pointer to an array giving the permissi-
						  ble  types  for  each  argument to the function
						  which will need to be freed up using Tcl_Free.

       Tcl_MathProc    **procPtr	(out)	  Points to a variable that will be set  to  con-
						  tain	a  pointer to the implementation code for
						  the function (or NULL if the function is imple-
						  mented directly in bytecode.)

       ClientData      *clientDataPtr	(out)	  Points  to  a variable that will be set to con-
						  tain the clientData argument passed to Tcl_Cre-
						  ateMathFunc  when  the  function was created if
						  the function is  not	implemented  directly  in

       CONST char      *pattern 	(in)	  Pattern  to  match against function names so as
						  to filter them (by passing to Tcl_StringMatch),
						  or NULL to not apply any filter.

       Tcl allows a number of mathematical functions to be used in expressions, such as sin, cos,
       and hypot.  Tcl_CreateMathFunc allows applications to add additional  functions	to  those
       already	provided  by Tcl or to replace existing functions.  Name is the name of the func-
       tion as it will appear in expressions.  If name doesn't already exist as a function then a
       new  function  is  created.   If  it  does  exist, then the existing function is replaced.
       NumArgs and argTypes describe the arguments to the function.  Each entry in  the  argTypes
       array  must be one of TCL_INT, TCL_DOUBLE, TCL_WIDE_INT, or TCL_EITHER to indicate whether |
       the corresponding argument must be an integer, a double-precision floating value,  a  wide |
       (64-bit) integer, or any, respectively.

       Whenever  the function is invoked in an expression Tcl will invoke proc.  Proc should have
       arguments and result that match the type Tcl_MathProc:
	      typedef int Tcl_MathProc(
		ClientData clientData,
		Tcl_Interp *interp,
		Tcl_Value *args,
		Tcl_Value *resultPtr);

       When proc is invoked the clientData and interp arguments will be the same as those  passed
       to Tcl_CreateMathFunc.  Args will point to an array of numArgs Tcl_Value structures, which
       describe the actual arguments to the function:						  |
	      typedef struct Tcl_Value {							  |
		Tcl_ValueType type;								  |
		long intValue;									  |
		double doubleValue;								  |
		Tcl_WideInt wideValue;								  |
	      } Tcl_Value;									  |

       The type field indicates the type of the argument and is one  of  TCL_INT,  TCL_DOUBLE  or |
       TCL_WIDE_INT.   It  will  match	the  argTypes value specified for the function unless the
       argTypes value was TCL_EITHER. Tcl converts the argument supplied in the expression to the
       type  requested	in  argTypes,  if  that is necessary.  Depending on the value of the type
       field, the intValue, doubleValue or wideValue field will contain the actual value  of  the |

       Proc should compute its result and store it either as an integer in resultPtr->intValue or
       as a floating value in resultPtr->doubleValue.  It should set also resultPtr->type to  one
       of TCL_INT, TCL_DOUBLE or TCL_WIDE_INT to indicate which value was set.	Under normal cir- |
       cumstances proc should return TCL_OK.  If an error occurs while	executing  the	function,
       proc should return TCL_ERROR and leave an error message in the interpreter's result.

       Tcl_GetMathFuncInfo retrieves the values associated with function name that were passed to |
       a preceding Tcl_CreateMathFunc call.  Normally, the return code is TCL_OK but if the named |
       function  does  not  exist,  TCL_ERROR  is  returned and an error message is placed in the |
       interpreter's result.									  |

       If an error did not occur, the array reference  placed  in  the	variable  pointed  to  by |
       argTypesPtr  is	newly  allocated, and should be released by passing it to Tcl_Free.  Some |
       functions (the standard set implemented in the core) are implemented directly at the byte- |
       code level; attempting to retrieve values for them causes a NULL to be stored in the vari- |
       able pointed to by procPtr and the variable pointed to by clientDataPtr will not be  modi- |
       fied.											  |

       Tcl_ListMathFuncs returns a Tcl object containing a list of all the math functions defined |
       in the interpreter whose name matches pattern.  In the case of an error, NULL is  returned |
       and  an error message is left in the interpreter result, and otherwise the returned object |
       will have a reference count of zero.

       expression, mathematical function

       expr(n), info(n), Tcl_Free(3), Tcl_NewListObj(3)

Tcl					       8.4			    Tcl_CreateMathFunc(3)

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