254 lines
10 KiB
Groff
254 lines
10 KiB
Groff
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'\"
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'\" Copyright (c) 1996-1997 Sun Microsystems, Inc.
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'\"
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'\" See the file "license.terms" for information on usage and redistribution
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'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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'\"
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.TH Tcl_ListObj 3 8.0 Tcl "Tcl Library Procedures"
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.so man.macros
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.BS
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.SH NAME
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Tcl_ListObjAppendList, Tcl_ListObjAppendElement, Tcl_NewListObj, Tcl_SetListObj, Tcl_ListObjGetElements, Tcl_ListObjLength, Tcl_ListObjIndex, Tcl_ListObjReplace \- manipulate Tcl values as lists
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.SH SYNOPSIS
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.nf
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\fB#include <tcl.h>\fR
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.sp
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int
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\fBTcl_ListObjAppendList\fR(\fIinterp, listPtr, elemListPtr\fR)
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.sp
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int
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\fBTcl_ListObjAppendElement\fR(\fIinterp, listPtr, objPtr\fR)
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.sp
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Tcl_Obj *
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\fBTcl_NewListObj\fR(\fIobjc, objv\fR)
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.sp
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\fBTcl_SetListObj\fR(\fIobjPtr, objc, objv\fR)
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.sp
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int
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\fBTcl_ListObjGetElements\fR(\fIinterp, listPtr, objcPtr, objvPtr\fR)
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.sp
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int
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\fBTcl_ListObjLength\fR(\fIinterp, listPtr, intPtr\fR)
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.sp
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int
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\fBTcl_ListObjIndex\fR(\fIinterp, listPtr, index, objPtrPtr\fR)
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.sp
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int
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\fBTcl_ListObjReplace\fR(\fIinterp, listPtr, first, count, objc, objv\fR)
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.SH ARGUMENTS
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.AS "Tcl_Obj *const" *elemListPtr in/out
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.AP Tcl_Interp *interp in
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If an error occurs while converting a value to be a list value,
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an error message is left in the interpreter's result value
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unless \fIinterp\fR is NULL.
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.AP Tcl_Obj *listPtr in/out
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Points to the list value to be manipulated.
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If \fIlistPtr\fR does not already point to a list value,
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an attempt will be made to convert it to one.
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.AP Tcl_Obj *elemListPtr in/out
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For \fBTcl_ListObjAppendList\fR, this points to a list value
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containing elements to be appended onto \fIlistPtr\fR.
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Each element of *\fIelemListPtr\fR will
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become a new element of \fIlistPtr\fR.
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If *\fIelemListPtr\fR is not NULL and
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does not already point to a list value,
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an attempt will be made to convert it to one.
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.AP Tcl_Obj *objPtr in
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For \fBTcl_ListObjAppendElement\fR,
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points to the Tcl value that will be appended to \fIlistPtr\fR.
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For \fBTcl_SetListObj\fR,
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this points to the Tcl value that will be converted to a list value
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containing the \fIobjc\fR elements of the array referenced by \fIobjv\fR.
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.AP int *objcPtr in
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Points to location where \fBTcl_ListObjGetElements\fR
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stores the number of element values in \fIlistPtr\fR.
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.AP Tcl_Obj ***objvPtr out
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A location where \fBTcl_ListObjGetElements\fR stores a pointer to an array
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of pointers to the element values of \fIlistPtr\fR.
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.AP int objc in
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The number of Tcl values that \fBTcl_NewListObj\fR
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will insert into a new list value,
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and \fBTcl_ListObjReplace\fR will insert into \fIlistPtr\fR.
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For \fBTcl_SetListObj\fR,
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the number of Tcl values to insert into \fIobjPtr\fR.
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.AP "Tcl_Obj *const" objv[] in
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An array of pointers to values.
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\fBTcl_NewListObj\fR will insert these values into a new list value
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and \fBTcl_ListObjReplace\fR will insert them into an existing \fIlistPtr\fR.
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Each value will become a separate list element.
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.AP int *intPtr out
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Points to location where \fBTcl_ListObjLength\fR
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stores the length of the list.
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.AP int index in
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Index of the list element that \fBTcl_ListObjIndex\fR
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is to return.
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The first element has index 0.
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.AP Tcl_Obj **objPtrPtr out
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Points to place where \fBTcl_ListObjIndex\fR is to store
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a pointer to the resulting list element value.
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.AP int first in
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Index of the starting list element that \fBTcl_ListObjReplace\fR
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is to replace.
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The list's first element has index 0.
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.AP int count in
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The number of elements that \fBTcl_ListObjReplace\fR
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is to replace.
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.BE
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.SH DESCRIPTION
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.PP
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Tcl list values have an internal representation that supports
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the efficient indexing and appending.
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The procedures described in this man page are used to
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create, modify, index, and append to Tcl list values from C code.
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.PP
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\fBTcl_ListObjAppendList\fR and \fBTcl_ListObjAppendElement\fR
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both add one or more values
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to the end of the list value referenced by \fIlistPtr\fR.
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\fBTcl_ListObjAppendList\fR appends each element of the list value
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referenced by \fIelemListPtr\fR while
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\fBTcl_ListObjAppendElement\fR appends the single value
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referenced by \fIobjPtr\fR.
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Both procedures will convert the value referenced by \fIlistPtr\fR
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to a list value if necessary.
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If an error occurs during conversion,
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both procedures return \fBTCL_ERROR\fR and leave an error message
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in the interpreter's result value if \fIinterp\fR is not NULL.
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Similarly, if \fIelemListPtr\fR does not already refer to a list value,
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\fBTcl_ListObjAppendList\fR will attempt to convert it to one
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and if an error occurs during conversion,
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will return \fBTCL_ERROR\fR
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and leave an error message in the interpreter's result value
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if interp is not NULL.
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Both procedures invalidate any old string representation of \fIlistPtr\fR
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and, if it was converted to a list value,
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free any old internal representation.
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Similarly, \fBTcl_ListObjAppendList\fR frees any old internal representation
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of \fIelemListPtr\fR if it converts it to a list value.
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After appending each element in \fIelemListPtr\fR,
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\fBTcl_ListObjAppendList\fR increments the element's reference count
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since \fIlistPtr\fR now also refers to it.
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For the same reason, \fBTcl_ListObjAppendElement\fR
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increments \fIobjPtr\fR's reference count.
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If no error occurs,
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the two procedures return \fBTCL_OK\fR after appending the values.
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.PP
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\fBTcl_NewListObj\fR and \fBTcl_SetListObj\fR
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create a new value or modify an existing value to hold
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the \fIobjc\fR elements of the array referenced by \fIobjv\fR
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where each element is a pointer to a Tcl value.
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If \fIobjc\fR is less than or equal to zero,
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they return an empty value. If \fIobjv\fR is NULL, the resulting list
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contains 0 elements, with reserved space in an internal representation
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for \fIobjc\fR more elements (to avoid its reallocation later).
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The new value's string representation is left invalid.
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The two procedures increment the reference counts
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of the elements in \fIobjc\fR since the list value now refers to them.
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The new list value returned by \fBTcl_NewListObj\fR
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has reference count zero.
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.PP
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\fBTcl_ListObjGetElements\fR returns a count and a pointer to an array of
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the elements in a list value. It returns the count by storing it in the
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address \fIobjcPtr\fR. Similarly, it returns the array pointer by storing
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it in the address \fIobjvPtr\fR.
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The memory pointed to is managed by Tcl and should not be freed or written
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to by the caller. If the list is empty, 0 is stored at \fIobjcPtr\fR
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and NULL at \fIobjvPtr\fR.
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If \fIlistPtr\fR is not already a list value, \fBTcl_ListObjGetElements\fR
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will attempt to convert it to one; if the conversion fails, it returns
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\fBTCL_ERROR\fR and leaves an error message in the interpreter's result
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value if \fIinterp\fR is not NULL.
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Otherwise it returns \fBTCL_OK\fR after storing the count and array pointer.
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.PP
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\fBTcl_ListObjLength\fR returns the number of elements in the list value
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referenced by \fIlistPtr\fR.
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It returns this count by storing an integer in the address \fIintPtr\fR.
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If the value is not already a list value,
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\fBTcl_ListObjLength\fR will attempt to convert it to one;
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if the conversion fails, it returns \fBTCL_ERROR\fR
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and leaves an error message in the interpreter's result value
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if \fIinterp\fR is not NULL.
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Otherwise it returns \fBTCL_OK\fR after storing the list's length.
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.PP
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The procedure \fBTcl_ListObjIndex\fR returns a pointer to the value
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at element \fIindex\fR in the list referenced by \fIlistPtr\fR.
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It returns this value by storing a pointer to it
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in the address \fIobjPtrPtr\fR.
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If \fIlistPtr\fR does not already refer to a list value,
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\fBTcl_ListObjIndex\fR will attempt to convert it to one;
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if the conversion fails, it returns \fBTCL_ERROR\fR
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and leaves an error message in the interpreter's result value
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if \fIinterp\fR is not NULL.
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If the index is out of range,
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that is, \fIindex\fR is negative or
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greater than or equal to the number of elements in the list,
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\fBTcl_ListObjIndex\fR stores a NULL in \fIobjPtrPtr\fR
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and returns \fBTCL_OK\fR.
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Otherwise it returns \fBTCL_OK\fR after storing the element's
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value pointer.
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The reference count for the list element is not incremented;
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the caller must do that if it needs to retain a pointer to the element.
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.PP
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\fBTcl_ListObjReplace\fR replaces zero or more elements
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of the list referenced by \fIlistPtr\fR
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with the \fIobjc\fR values in the array referenced by \fIobjv\fR.
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If \fIlistPtr\fR does not point to a list value,
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\fBTcl_ListObjReplace\fR will attempt to convert it to one;
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if the conversion fails, it returns \fBTCL_ERROR\fR
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and leaves an error message in the interpreter's result value
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if \fIinterp\fR is not NULL.
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Otherwise, it returns \fBTCL_OK\fR after replacing the values.
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If \fIobjv\fR is NULL, no new elements are added.
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If the argument \fIfirst\fR is zero or negative,
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it refers to the first element.
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If \fIfirst\fR is greater than or equal to the
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number of elements in the list, then no elements are deleted;
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the new elements are appended to the list.
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\fIcount\fR gives the number of elements to replace.
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If \fIcount\fR is zero or negative then no elements are deleted;
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the new elements are simply inserted before the one
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designated by \fIfirst\fR.
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\fBTcl_ListObjReplace\fR invalidates \fIlistPtr\fR's
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old string representation.
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The reference counts of any elements inserted from \fIobjv\fR
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are incremented since the resulting list now refers to them.
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Similarly, the reference counts for any replaced values are decremented.
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.PP
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Because \fBTcl_ListObjReplace\fR combines
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both element insertion and deletion,
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it can be used to implement a number of list operations.
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For example, the following code inserts the \fIobjc\fR values
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referenced by the array of value pointers \fIobjv\fR
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just before the element \fIindex\fR of the list referenced by \fIlistPtr\fR:
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.PP
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.CS
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result = \fBTcl_ListObjReplace\fR(interp, listPtr, index, 0,
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objc, objv);
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.CE
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.PP
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Similarly, the following code appends the \fIobjc\fR values
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referenced by the array \fIobjv\fR
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to the end of the list \fIlistPtr\fR:
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.PP
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.CS
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result = \fBTcl_ListObjLength\fR(interp, listPtr, &length);
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if (result == TCL_OK) {
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result = \fBTcl_ListObjReplace\fR(interp, listPtr, length, 0,
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objc, objv);
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}
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.CE
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.PP
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The \fIcount\fR list elements starting at \fIfirst\fR can be deleted
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by simply calling \fBTcl_ListObjReplace\fR
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with a NULL \fIobjvPtr\fR:
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.PP
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.CS
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result = \fBTcl_ListObjReplace\fR(interp, listPtr, first, count,
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0, NULL);
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.CE
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.SH "SEE ALSO"
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Tcl_NewObj(3), Tcl_DecrRefCount(3), Tcl_IncrRefCount(3), Tcl_GetObjResult(3)
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.SH KEYWORDS
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append, index, insert, internal representation, length, list, list value,
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list type, value, value type, replace, string representation
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