'\" '\" Copyright (c) 1996-1997 Sun Microsystems, Inc. '\" Contributions from Don Porter, NIST, 2005. (not subject to US copyright) '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" '\" RCS: @(#) $Id: BoolObj.3,v 1.11.2.1 2009/11/27 14:53:54 dkf Exp $ '\" .so man.macros .TH Tcl_BooleanObj 3 8.5 Tcl "Tcl Library Procedures" .BS .SH NAME Tcl_NewBooleanObj, Tcl_SetBooleanObj, Tcl_GetBooleanFromObj \- store/retrieve boolean value in a Tcl_Obj .SH SYNOPSIS .nf \fB#include \fR .sp Tcl_Obj * \fBTcl_NewBooleanObj\fR(\fIboolValue\fR) .sp \fBTcl_SetBooleanObj\fR(\fIobjPtr, boolValue\fR) .sp int \fBTcl_GetBooleanFromObj\fR(\fIinterp, objPtr, boolPtr\fR) .SH ARGUMENTS .AS Tcl_Interp boolValue in/out .AP int boolValue in Integer value to be stored as a boolean value in a Tcl_Obj. .AP Tcl_Obj *objPtr in/out Points to the Tcl_Obj in which to store, or from which to retrieve a boolean value. .AP Tcl_Interp *interp in/out If a boolean value cannot be retrieved, an error message is left in the interpreter's result object unless \fIinterp\fR is NULL. .AP int *boolPtr out Points to place where \fBTcl_GetBooleanFromObj\fR stores the boolean value (0 or 1) obtained from \fIobjPtr\fR. .BE .SH DESCRIPTION .PP These procedures are used to pass boolean values to and from Tcl as Tcl_Obj's. When storing a boolean value into a Tcl_Obj, any non-zero integer value in \fIboolValue\fR is taken to be the boolean value \fB1\fR, and the integer value \fB0\fR is taken to be the boolean value \fB0\fR. .PP \fBTcl_NewBooleanObj\fR creates a new Tcl_Obj, stores the boolean value \fIboolValue\fR in it, and returns a pointer to the new Tcl_Obj. The new Tcl_Obj has reference count of zero. .PP \fBTcl_SetBooleanObj\fR accepts \fIobjPtr\fR, a pointer to an existing Tcl_Obj, and stores in the Tcl_Obj \fI*objPtr\fR the boolean value \fIboolValue\fR. This is a write operation on \fI*objPtr\fR, so \fIobjPtr\fR must be unshared. Attempts to write to a shared Tcl_Obj will panic. A successful write of \fIboolValue\fR into \fI*objPtr\fR implies the freeing of any former value stored in \fI*objPtr\fR. .PP \fBTcl_GetBooleanFromObj\fR attempts to retrieve a boolean value from the value stored in \fI*objPtr\fR. If \fIobjPtr\fR holds a string value recognized by \fBTcl_GetBoolean\fR, then the recognized boolean value is written at the address given by \fIboolPtr\fR. If \fIobjPtr\fR holds any value recognized as a number by Tcl, then if that value is zero a 0 is written at the address given by \fIboolPtr\fR and if that value is non-zero a 1 is written at the address given by \fIboolPtr\fR. In all cases where a value is written at the address given by \fIboolPtr\fR, \fBTcl_GetBooleanFromObj\fR returns \fBTCL_OK\fR. If the value of \fIobjPtr\fR does not meet any of the conditions above, then \fBTCL_ERROR\fR is returned and an error message is left in the interpreter's result unless \fIinterp\fR is NULL. \fBTcl_GetBooleanFromObj\fR may also make changes to the internal fields of \fI*objPtr\fR so that future calls to \fBTcl_GetBooleanFromObj\fR on the same \fIobjPtr\fR can be performed more efficiently. .PP Note that the routines \fBTcl_GetBooleanFromObj\fR and \fBTcl_GetBoolean\fR are not functional equivalents. The set of values for which \fBTcl_GetBooleanFromObj\fR will return \fBTCL_OK\fR is strictly larger than the set of values for which \fBTcl_GetBoolean\fR will do the same. For example, the value .QW 5 passed to \fBTcl_GetBooleanFromObj\fR will lead to a \fBTCL_OK\fR return (and the boolean value 1), while the same value passed to \fBTcl_GetBoolean\fR will lead to a \fBTCL_ERROR\fR return. .SH "SEE ALSO" Tcl_NewObj, Tcl_IsShared, Tcl_GetBoolean .SH KEYWORDS boolean, object