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Tcl_CreateMathFunc(3)                      Tcl Library Procedures                      Tcl_CreateMathFunc(3)



____________________________________________________________________________________________________________

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

SYNOPSIS
       #include <tcl.h>

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

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

       Tcl_Obj *
       Tcl_ListMathFuncs(interp, pattern)

ARGUMENTS
       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 contain the num-ber number
                                                  ber of arguments to the function.

       Tcl_ValueType **argTypesPtr (out)          Points to a variable that will be set to contain a pointer
                                                  to an array giving the permissible 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 contain a pointer
                                                  to the implementation code for the function  (or  NULL  if
                                                  the function is implemented directly in bytecode).

       ClientData *clientDataPtr (out)            Points  to  a  variable  that  will  be set to contain the
                                                  clientData argument passed to Tcl_CreateMathFunc when  the
                                                  function  was  created  if the function is not implemented
                                                  directly in bytecode.

       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.
____________________________________________________________________________________________________________


DESCRIPTION
       Tcl allows a number of mathematical functions to be used in expressions, such as sin, cos, and hypot.
       These  functions are represented by commands in the namespace, tcl::mathfunc.  The Tcl_CreateMathFunc
       function is an obsolete way for applications to add additional functions to those already provided by
       Tcl or to replace existing functions.  It should not be used by new applications, which should create
       math functions using Tcl_CreateObjCommand to create a command in the tcl::mathfunc namespace.

       In the Tcl_CreateMathFunc interface, Name is the name of the function as it will  appear  in  expres-sions. expressions.
       sions.   If  name does not already exist in the ::tcl::mathfunc namespace, then a new command is cre-ated created
       ated in that namespace.  If name 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_Cre-ateMathFunc. Tcl_CreateMathFunc.
       ateMathFunc.   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 argument.

       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 circumstances  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  preced-ing preceding
       ing  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, and those defined by placing commands in the tcl::mathfunc namespace) do not
       have  argument type information; attempting to retrieve values for them causes a NULL to be stored in
       the variable pointed to by procPtr and the variable pointed to by clientDataPtr will not be modified.
       The  variable  pointed  to by numArgsPointer will contain -1, and no argument types will be stored in
       the variable pointed to by argTypesPointer.

       Tcl_ListMathFuncs returns a Tcl object containing a list of all the math  functions  defined  in  the
       interpreter whose name matches pattern.  The returned object has a reference count of zero.


SEE ALSO
       expr(n), info(n), Tcl_CreateObjCommand(3), Tcl_Free(3), Tcl_NewListObj(3)


KEYWORDS
       expression, mathematical function



Tcl                                                  8.4                               Tcl_CreateMathFunc(3)