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+'\"
+'\" Copyright (c) 1989-1993 The Regents of the University of California.
+'\" Copyright (c) 1994-1997 Sun Microsystems, Inc.
+'\"
+'\" See the file "license.terms" for information on usage and redistribution
+'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+'\" 
+'\" SCCS: @(#) SetVar.3 1.30 97/10/10 16:10:36
+'\" 
+.so man.macros
+.TH Tcl_SetVar 3 7.4 Tcl "Tcl Library Procedures"
+.BS
+.SH NAME
+Tcl_SetVar, Tcl_SetVar2, Tcl_GetVar, Tcl_GetVar2, Tcl_UnsetVar, Tcl_UnsetVar2 \- manipulate Tcl variables
+.SH SYNOPSIS
+.nf
+\fB#include <tcl.h>\fR
+.sp
+char *
+\fBTcl_SetVar\fR(\fIinterp, varName, newValue, flags\fR)
+.sp
+char *
+\fBTcl_SetVar2\fR(\fIinterp, name1, name2, newValue, flags\fR)
+.sp
+char *
+\fBTcl_GetVar\fR(\fIinterp, varName, flags\fR)
+.sp
+char *
+\fBTcl_GetVar2\fR(\fIinterp, name1, name2, flags\fR)
+.sp
+int
+\fBTcl_UnsetVar\fR(\fIinterp, varName, flags\fR)
+.sp
+int
+\fBTcl_UnsetVar2\fR(\fIinterp, name1, name2, flags\fR)
+.SH ARGUMENTS
+.AS Tcl_Interp *newValue
+.AP Tcl_Interp *interp in
+Interpreter containing variable.
+.AP char *varName in
+Name of variable.
+May include a series of \fB::\fR namespace qualifiers
+to specify a variable in a particular namespace.
+May refer to a scalar variable or an element of
+an array variable.
+If the name references an element of an array, then it
+must be in writable memory:  Tcl will make temporary modifications 
+to it while looking up the name.
+.AP char *newValue in
+New value for variable.
+.AP int flags in
+OR-ed combination of bits providing additional information for
+operation. See below for valid values.
+.AP char *name1 in
+Name of scalar variable, or name of array variable if \fIname2\fR
+is non-NULL.
+May include a series of \fB::\fR namespace qualifiers
+to specify a variable in a particular namespace.
+.AP char *name2 in
+If non-NULL, gives name of element within array and \fIname1\fR
+must refer to an array variable.
+.BE
+
+.SH DESCRIPTION
+.PP
+These procedures may be used to create, modify, read, and delete
+Tcl variables from C code.
+.PP
+Note that \fBTcl_GetVar\fR and \fBTcl_SetVar\fR
+have been largely replaced by the
+object-based procedures \fBTcl_ObjGetVar2\fR and \fBTcl_ObjSetVar2\fR.
+Those object-based procedures read, modify, and create
+a variable whose name is held in a Tcl object instead of a string.
+They also return a pointer to the object
+which is the variable's value instead of returning a string.
+Operations on objects can be faster since objects
+hold an internal representation that can be manipulated more efficiently.
+.PP
+\fBTcl_SetVar\fR and \fBTcl_SetVar2\fR
+will create a new variable or modify an existing one.
+Both of these procedures set the given variable to the value
+given by \fInewValue\fR, and they return a pointer to a
+copy of the variable's new value, which is stored in Tcl's
+variable structure.
+Tcl keeps a private copy of the variable's value, so the caller
+may change \fInewValue\fR after these procedures return without
+affecting the value of the variable.
+If an error occurs in setting the variable (e.g. an array
+variable is referenced without giving an index into the array),
+they return NULL.
+.PP
+The name of the variable may be specified to
+\fBTcl_SetVar\fR and \fBTcl_SetVar2\fR in either of two ways.
+If \fBTcl_SetVar\fR is called, the variable name is given as
+a single string, \fIvarName\fR.
+If \fIvarName\fR contains an open parenthesis and ends with a
+close parenthesis, then the value between the parentheses is
+treated as an index (which can have any string value) and
+the characters before the first open
+parenthesis are treated as the name of an array variable.
+If \fIvarName\fR doesn't have parentheses as described above, then
+the entire string is treated as the name of a scalar variable.
+If \fBTcl_SetVar2\fR is called, then the array name and index
+have been separated by the caller into two separate strings,
+\fIname1\fR and \fIname2\fR respectively;  if \fIname2\fR is
+zero it means that a scalar variable is being referenced.
+.PP
+The \fIflags\fR argument may be used to specify any of several
+options to the procedures.
+It consists of an OR-ed combination of the following bits.
+Note that the flag bit TCL_PARSE_PART1 is only meaningful
+for the procedures Tcl_SetVar2 and Tcl_GetVar2.
+.TP
+\fBTCL_GLOBAL_ONLY\fR
+Under normal circumstances the procedures look up variables as follows:
+If a procedure call is active in \fIinterp\fR,
+a variable is looked up at the current level of procedure call.
+Otherwise, a variable is looked up first in the current namespace,
+then in the global namespace.
+However, if this bit is set in \fIflags\fR then the variable
+is looked up only in the global namespace
+even if there is a procedure call active.
+If both \fBTCL_GLOBAL_ONLY\fR and \fBTCL_NAMESPACE_ONLY\fR are given,
+\fBTCL_GLOBAL_ONLY\fR is ignored.
+.TP
+\fBTCL_NAMESPACE_ONLY\fR
+Under normal circumstances the procedures look up variables as follows:
+If a procedure call is active in \fIinterp\fR,
+a variable is looked up at the current level of procedure call.
+Otherwise, a variable is looked up first in the current namespace,
+then in the global namespace.
+However, if this bit is set in \fIflags\fR then the variable
+is looked up only in the current namespace
+even if there is a procedure call active.
+.TP
+\fBTCL_LEAVE_ERR_MSG\fR
+If an error is returned and this bit is set in \fIflags\fR, then
+an error message will be left in the interpreter's result,
+where it can be retrieved with \fBTcl_GetObjResult\fR
+or \fBTcl_GetStringResult\fR.
+If this flag bit isn't set then no error message is left
+and the interpreter's result will not be modified.
+.TP
+\fBTCL_APPEND_VALUE\fR
+If this bit is set then \fInewValue\fR is appended to the current
+value, instead of replacing it.
+If the variable is currently undefined, then this bit is ignored.
+.TP
+\fBTCL_LIST_ELEMENT\fR
+If this bit is set, then \fInewValue\fR is converted to a valid
+Tcl list element before setting (or appending to) the variable.
+A separator space is appended before the new list element unless
+the list element is going to be the first element in a list or
+sublist (i.e. the variable's current value is empty, or contains
+the single character ``{'', or ends in `` }'').
+.TP
+\fBTCL_PARSE_PART1\fR
+If this bit is set when calling \fITcl_SetVar2\fR and \fITcl_GetVar2\fR,
+\fIname1\fR may contain both an array and an element name:
+if the name contains an open parenthesis and ends with a
+close parenthesis, then the value between the parentheses is
+treated as an element name (which can have any string value) and
+the characters before the first open
+parenthesis are treated as the name of an array variable.
+If the flag TCL_PARSE_PART1 is given,
+\fIname2\fR should be NULL since the array and element names
+are taken from \fIname1\fR.
+.PP
+\fBTcl_GetVar\fR and \fBTcl_GetVar2\fR
+return the current value of a variable.
+The arguments to these procedures are treated in the same way
+as the arguments to \fBTcl_SetVar\fR and \fBTcl_SetVar2\fR.
+Under normal circumstances, the return value is a pointer
+to the variable's value (which is stored in Tcl's variable
+structure and will not change before the next call to \fBTcl_SetVar\fR
+or \fBTcl_SetVar2\fR).
+\fBTcl_GetVar\fR and \fBTcl_GetVar2\fR use the flag bits TCL_GLOBAL_ONLY
+and TCL_LEAVE_ERR_MSG, both of
+which have
+the same meaning as for \fBTcl_SetVar\fR.
+In addition, \fBTcl_GetVar2\fR uses the bit TCL_PARSE_PART1,
+which has the same meaning as for \fBTcl_SetVar2\fR.
+If an error occurs in reading the variable (e.g. the variable
+doesn't exist or an array element is specified for a scalar
+variable), then NULL is returned.
+.PP
+\fBTcl_UnsetVar\fR and \fBTcl_UnsetVar2\fR may be used to remove
+a variable, so that future calls to \fBTcl_GetVar\fR or \fBTcl_GetVar2\fR
+for the variable will return an error.
+The arguments to these procedures are treated in the same way
+as the arguments to \fBTcl_GetVar\fR and \fBTcl_GetVar2\fR.
+If the variable is successfully removed then TCL_OK is returned.
+If the variable cannot be removed because it doesn't exist then
+TCL_ERROR is returned.
+If an array element is specified, the given element is removed
+but the array remains.
+If an array name is specified without an index, then the entire
+array is removed.
+
+.SH "SEE ALSO"
+Tcl_GetObjResult, Tcl_GetStringResult, Tcl_ObjGetVar2, Tcl_ObjSetVar2, Tcl_TraceVar
+
+.SH KEYWORDS
+array, interpreter, object, scalar, set, unset, variable