Tcl_CreateMathFunc(3tcl)
______________________________________________________________________________
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
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
number 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 func-
tion 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 implementa-
tion 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 imple-
mented directly in bytecode.
CONST char *pattern (in) Pattern to match against
function names so as to fil-
ter 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. Tcl_CreateMathFunc allows applica-
tions to add additional functions to those already provided by Tcl or
to replace existing functions. Name is the name of the function as it
will appear in expressions. If name doesn't already exist as a func-
tion then a new function is created. If it does exist, then the exist-
ing 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 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) are implemented directly at the bytecode level; 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. |
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.
KEYWORDS
expression, mathematical function
SEE ALSO
expr(n), info(n), Tcl_Free(3), Tcl_NewListObj(3)
Tcl 8.4 Tcl_CreateMathFunc(3)
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