diff options
Diffstat (limited to 'doc/Object.3')
| -rw-r--r-- | doc/Object.3 | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/doc/Object.3 b/doc/Object.3 index 3b6abc8..00b4cec 100644 --- a/doc/Object.3 +++ b/doc/Object.3 @@ -4,7 +4,7 @@ '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" -'\" RCS: @(#) $Id: Object.3,v 1.21 2008/07/27 22:18:21 nijtmans Exp $ +'\" RCS: @(#) $Id: Object.3,v 1.22 2008/10/15 10:43:37 dkf Exp $ '\" .so man.macros .TH Tcl_Obj 3 8.5 Tcl "Tcl Library Procedures" @@ -109,6 +109,7 @@ by defining their own \fBTcl_ObjType\fR structs. .PP Each Tcl object is represented by a \fBTcl_Obj\fR structure which is defined as follows. +.PP .CS typedef struct Tcl_Obj { int \fIrefCount\fR; @@ -131,6 +132,7 @@ typedef struct Tcl_Obj { } \fIinternalRep\fR; } \fBTcl_Obj\fR; .CE +.PP The \fIbytes\fR and the \fIlength\fR members together hold an object's UTF-8 string representation, which is a \fIcounted string\fR not containing null bytes (UTF-8 null @@ -232,20 +234,26 @@ to see how to create a new object type. .PP As an example of the lifetime of an object, consider the following sequence of commands: +.PP .CS \fBset x 123\fR .CE +.PP This assigns to \fIx\fR an untyped object whose \fIbytes\fR member points to \fB123\fR and \fIlength\fR member contains 3. The object's \fItypePtr\fR member is NULL. +.PP .CS \fBputs "x is $x"\fR .CE +.PP \fIx\fR's string representation is valid (since \fIbytes\fR is non-NULL) and is fetched for the command. +.PP .CS \fBincr x\fR .CE +.PP The \fBincr\fR command first gets an integer from \fIx\fR's object by calling \fBTcl_GetIntFromObj\fR. This procedure checks whether the object is already an integer object. @@ -260,9 +268,11 @@ then invalidates its string representation (by calling \fBTcl_InvalidateStringRep\fR) since the string representation no longer corresponds to the internal representation. +.PP .CS \fBputs "x is now $x"\fR .CE +.PP The string representation of \fIx\fR's object is needed and is recomputed. The string representation is now \fB124\fR |