Tcl_CreateMathFunc(3) Tcl Library Procedures Tcl_CreateMathFunc(3)
NAME
Tcl_CreateMathFunc, Tcl_GetMathFuncInfo, Tcl_ListMathFuncs - Define,
query and enumerate math functions 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
Interpreter in which new function will be defined. Name for new func-
tion. Number of arguments to new function; also gives size of
argTypes array. Points to an array giving the permissible types for
each argument to function. Procedure that implements the function.
Arbitrary one-word value to pass to proc when it is invoked. Points to
a variable that will be set to contain the number of arguments to the
function. Points to a variable that will be set to contain a pointer
to an array giving the permissible types for each argument to the func-
tion which will need to be freed up using Tcl_Free. Points to a vari-
able 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). 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. Pat-
tern 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 expres-
sions, such as sin, cos, and hypot. These functions are represented by
commands in the namespace, tcl::mathfunc. The Tcl_CreateMathFunc func-
tion 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 func-
tions using Tcl_CreateObjCommand to create a command in the tcl::math-
func namespace.
In the Tcl_CreateMathFunc interface, Name is the name of the function
as it will appear in expressions. If name does not already exist in
the ::tcl::mathfunc namespace, then a new command is created 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 argu-
ment 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 argu-
ments 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 con-
tain 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 circum-
stances 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 inter-
preter'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 con-
tain -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_NewLis-
tObj(3)
KEYWORDS
expression, mathematical function
Tcl 8.4 Tcl_CreateMathFunc(3)
CrtMathFnc 8.5.4 - Generated Sun Aug 17 21:08:07 CDT 2008