1 | '\" |
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2 | '\" Copyright (c) 1989-1993 The Regents of the University of California. |
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3 | '\" Copyright (c) 1994-1996 Sun Microsystems, Inc. |
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4 | '\" |
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5 | '\" See the file "license.terms" for information on usage and redistribution |
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6 | '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
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7 | '\" |
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8 | '\" RCS: @(#) $Id: CrtMathFnc.3,v 1.17 2007/12/13 15:22:30 dgp Exp $ |
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9 | '\" |
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10 | .so man.macros |
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11 | .TH Tcl_CreateMathFunc 3 8.4 Tcl "Tcl Library Procedures" |
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12 | .BS |
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13 | .SH NAME |
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14 | Tcl_CreateMathFunc, Tcl_GetMathFuncInfo, Tcl_ListMathFuncs \- Define, query and enumerate math functions for expressions |
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15 | .SH SYNOPSIS |
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16 | .nf |
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17 | \fB#include <tcl.h>\fR |
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18 | .sp |
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19 | void |
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20 | \fBTcl_CreateMathFunc\fR(\fIinterp, name, numArgs, argTypes, proc, clientData\fR) |
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21 | .sp |
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22 | int |
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23 | \fBTcl_GetMathFuncInfo\fR(\fIinterp, name, numArgsPtr, argTypesPtr, procPtr, |
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24 | clientDataPtr\fR) |
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25 | .sp |
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26 | Tcl_Obj * |
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27 | \fBTcl_ListMathFuncs\fR(\fIinterp, pattern\fR) |
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28 | .SH ARGUMENTS |
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29 | .AS Tcl_ValueType *clientDataPtr out |
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30 | .AP Tcl_Interp *interp in |
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31 | Interpreter in which new function will be defined. |
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32 | .AP "const char" *name in |
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33 | Name for new function. |
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34 | .AP int numArgs in |
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35 | Number of arguments to new function; also gives size of \fIargTypes\fR array. |
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36 | .AP Tcl_ValueType *argTypes in |
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37 | Points to an array giving the permissible types for each argument to |
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38 | function. |
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39 | .AP Tcl_MathProc *proc in |
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40 | Procedure that implements the function. |
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41 | .AP ClientData clientData in |
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42 | Arbitrary one-word value to pass to \fIproc\fR when it is invoked. |
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43 | .AP int *numArgsPtr out |
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44 | Points to a variable that will be set to contain the number of |
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45 | arguments to the function. |
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46 | .AP Tcl_ValueType **argTypesPtr out |
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47 | Points to a variable that will be set to contain a pointer to an array |
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48 | giving the permissible types for each argument to the function which |
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49 | will need to be freed up using \fITcl_Free\fR. |
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50 | .AP Tcl_MathProc **procPtr out |
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51 | Points to a variable that will be set to contain a pointer to the |
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52 | implementation code for the function (or NULL if the function is |
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53 | implemented directly in bytecode). |
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54 | .AP ClientData *clientDataPtr out |
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55 | Points to a variable that will be set to contain the clientData |
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56 | argument passed to \fITcl_CreateMathFunc\fR when the function was |
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57 | created if the function is not implemented directly in bytecode. |
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58 | .AP "const char" *pattern in |
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59 | Pattern to match against function names so as to filter them (by |
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60 | passing to \fITcl_StringMatch\fR), or NULL to not apply any filter. |
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61 | .BE |
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62 | |
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63 | .SH DESCRIPTION |
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64 | .PP |
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65 | Tcl allows a number of mathematical functions to be used in |
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66 | expressions, such as \fBsin\fR, \fBcos\fR, and \fBhypot\fR. |
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67 | These functions are represented by commands in the namespace, |
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68 | \fBtcl::mathfunc\fR. The \fBTcl_CreateMathFunc\fR function is |
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69 | an obsolete way for applications to add additional functions |
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70 | to those already provided by Tcl or to replace existing functions. |
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71 | It should not be used by new applications, which should create |
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72 | math functions using \fBTcl_CreateObjCommand\fR to create a command |
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73 | in the \fBtcl::mathfunc\fR namespace. |
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74 | .PP |
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75 | In the \fBTcl_CreateMathFunc\fR interface, |
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76 | \fIName\fR is the name of the function as it will appear in expressions. |
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77 | If \fIname\fR does not already exist in the \fB::tcl::mathfunc\fR |
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78 | namespace, then a new command is created in that namespace. |
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79 | If \fIname\fR does exist, then the existing function is replaced. |
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80 | \fINumArgs\fR and \fIargTypes\fR describe the arguments to the function. |
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81 | Each entry in the \fIargTypes\fR array must be |
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82 | one of \fBTCL_INT\fR, \fBTCL_DOUBLE\fR, \fBTCL_WIDE_INT\fR, |
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83 | or \fBTCL_EITHER\fR to indicate whether the corresponding argument must be an |
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84 | integer, a double-precision floating value, a wide (64-bit) integer, |
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85 | or any, respectively. |
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86 | .PP |
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87 | Whenever the function is invoked in an expression Tcl will invoke |
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88 | \fIproc\fR. \fIProc\fR should have arguments and result that match |
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89 | the type \fBTcl_MathProc\fR: |
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90 | .CS |
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91 | typedef int Tcl_MathProc( |
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92 | ClientData \fIclientData\fR, |
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93 | Tcl_Interp *\fIinterp\fR, |
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94 | Tcl_Value *\fIargs\fR, |
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95 | Tcl_Value *\fIresultPtr\fR); |
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96 | .CE |
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97 | .PP |
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98 | When \fIproc\fR is invoked the \fIclientData\fR and \fIinterp\fR |
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99 | arguments will be the same as those passed to \fBTcl_CreateMathFunc\fR. |
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100 | \fIArgs\fR will point to an array of \fInumArgs\fR Tcl_Value structures, |
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101 | which describe the actual arguments to the function: |
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102 | .CS |
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103 | typedef struct Tcl_Value { |
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104 | Tcl_ValueType \fItype\fR; |
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105 | long \fIintValue\fR; |
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106 | double \fIdoubleValue\fR; |
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107 | Tcl_WideInt \fIwideValue\fR; |
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108 | } Tcl_Value; |
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109 | .CE |
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110 | .PP |
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111 | The \fItype\fR field indicates the type of the argument and is |
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112 | one of \fBTCL_INT\fR, \fBTCL_DOUBLE\fR or \fBTCL_WIDE_INT\fR. |
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113 | It will match the \fIargTypes\fR value specified for the function unless |
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114 | the \fIargTypes\fR value was \fBTCL_EITHER\fR. Tcl converts |
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115 | the argument supplied in the expression to the type requested in |
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116 | \fIargTypes\fR, if that is necessary. |
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117 | Depending on the value of the \fItype\fR field, the \fIintValue\fR, |
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118 | \fIdoubleValue\fR or \fIwideValue\fR |
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119 | field will contain the actual value of the argument. |
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120 | .PP |
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121 | \fIProc\fR should compute its result and store it either as an integer |
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122 | in \fIresultPtr->intValue\fR or as a floating value in |
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123 | \fIresultPtr->doubleValue\fR. |
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124 | It should set also \fIresultPtr->type\fR to one of |
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125 | \fBTCL_INT\fR, \fBTCL_DOUBLE\fR or \fBTCL_WIDE_INT\fR |
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126 | to indicate which value was set. |
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127 | Under normal circumstances \fIproc\fR should return \fBTCL_OK\fR. |
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128 | If an error occurs while executing the function, \fIproc\fR should |
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129 | return \fBTCL_ERROR\fR and leave an error message in the interpreter's result. |
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130 | .PP |
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131 | \fBTcl_GetMathFuncInfo\fR retrieves the values associated with |
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132 | function \fIname\fR that were passed to a preceding |
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133 | \fBTcl_CreateMathFunc\fR call. Normally, the return code is |
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134 | \fBTCL_OK\fR but if the named function does not exist, \fBTCL_ERROR\fR |
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135 | is returned and an error message is placed in the interpreter's |
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136 | result. |
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137 | .PP |
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138 | If an error did not occur, the array reference placed in the variable |
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139 | pointed to by \fIargTypesPtr\fR is newly allocated, and should be |
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140 | released by passing it to \fBTcl_Free\fR. Some functions (the |
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141 | standard set implemented in the core, and those defined by placing |
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142 | commands in the \fBtcl::mathfunc\fR namespace) do not have |
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143 | argument type information; attempting to retrieve values for |
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144 | them causes a NULL to be stored in the variable pointed to by |
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145 | \fIprocPtr\fR and the variable pointed to by \fIclientDataPtr\fR |
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146 | will not be modified. The variable pointed to by \fInumArgsPointer\fR |
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147 | will contain -1, and no argument types will be stored in the variable |
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148 | pointed to by \fIargTypesPointer\fR. |
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149 | .PP |
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150 | \fBTcl_ListMathFuncs\fR returns a Tcl object containing a list of all |
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151 | the math functions defined in the interpreter whose name matches |
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152 | \fIpattern\fR. The returned object has a reference count of zero. |
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153 | |
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154 | .SH "SEE ALSO" |
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155 | expr(n), info(n), Tcl_CreateObjCommand(3), Tcl_Free(3), Tcl_NewListObj(3) |
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156 | |
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157 | .SH KEYWORDS |
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158 | expression, mathematical function |
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