Tcl_CreateMathFunc(3)
Tcl_CreateMathFunc(3)Tcl Library Procedures Tcl_CreateMathFunc(3)
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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
Tcl_Interp *interp (in) Interpreter in
which new func-
tion will be
defined.
const char *name (in) Name for new
function.
int numArgs (in) Number of argu-
ments 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 vari-
able that will be
set to contain
Tcl Last change: 8.4 1
Tcl_CreateMathFunc(3)Tcl Library Procedures Tcl_CreateMathFunc(3)
the number of
arguments to the
function.
Tcl_ValueType **argTypesPtr (out) Points to a vari-
able 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 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).
ClientData *clientDataPtr (out) Points to a vari-
able 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.
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Tcl Last change: 8.4 2
Tcl_CreateMathFunc(3)Tcl Library Procedures Tcl_CreateMathFunc(3)
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 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 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 argument.
Tcl Last change: 8.4 3
Tcl_CreateMathFunc(3)Tcl Library Procedures Tcl_CreateMathFunc(3)
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 func-
tion, proc should return TCL_ERROR and leave an error mes-
sage 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 func-
tions (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 Last change: 8.4 4
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