'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
-'\" RCS: @(#) $Id: ObjectType.3,v 1.7 2002/08/16 13:45:36 dkf Exp $
-'\"
-'\" The definitions below are for supplemental macros used in Tcl/Tk
-'\" manual entries.
-'\"
-'\" .AP type name in/out ?indent?
-'\" Start paragraph describing an argument to a library procedure.
-'\" type is type of argument (int, etc.), in/out is either "in", "out",
-'\" or "in/out" to describe whether procedure reads or modifies arg,
-'\" and indent is equivalent to second arg of .IP (shouldn't ever be
-'\" needed; use .AS below instead)
-'\"
-'\" .AS ?type? ?name?
-'\" Give maximum sizes of arguments for setting tab stops. Type and
-'\" name are examples of largest possible arguments that will be passed
-'\" to .AP later. If args are omitted, default tab stops are used.
-'\"
-'\" .BS
-'\" Start box enclosure. From here until next .BE, everything will be
-'\" enclosed in one large box.
-'\"
-'\" .BE
-'\" End of box enclosure.
-'\"
-'\" .CS
-'\" Begin code excerpt.
-'\"
-'\" .CE
-'\" End code excerpt.
-'\"
-'\" .VS ?version? ?br?
-'\" Begin vertical sidebar, for use in marking newly-changed parts
-'\" of man pages. The first argument is ignored and used for recording
-'\" the version when the .VS was added, so that the sidebars can be
-'\" found and removed when they reach a certain age. If another argument
-'\" is present, then a line break is forced before starting the sidebar.
-'\"
-'\" .VE
-'\" End of vertical sidebar.
-'\"
-'\" .DS
-'\" Begin an indented unfilled display.
-'\"
-'\" .DE
-'\" End of indented unfilled display.
-'\"
-'\" .SO
-'\" Start of list of standard options for a Tk widget. The
-'\" options follow on successive lines, in four columns separated
-'\" by tabs.
-'\"
-'\" .SE
-'\" End of list of standard options for a Tk widget.
-'\"
-'\" .OP cmdName dbName dbClass
-'\" Start of description of a specific option. cmdName gives the
-'\" option's name as specified in the class command, dbName gives
-'\" the option's name in the option database, and dbClass gives
-'\" the option's class in the option database.
-'\"
-'\" .UL arg1 arg2
-'\" Print arg1 underlined, then print arg2 normally.
-'\"
-'\" RCS: @(#) $Id: man.macros,v 1.4 2000/08/25 06:18:32 ericm Exp $
-'\"
-'\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages.
+.TH Tcl_ObjType 3 8.0 Tcl "Tcl Library Procedures"
+.\" The -*- nroff -*- definitions below are for supplemental macros used
+.\" in Tcl/Tk manual entries.
+.\"
+.\" .AP type name in/out ?indent?
+.\" Start paragraph describing an argument to a library procedure.
+.\" type is type of argument (int, etc.), in/out is either "in", "out",
+.\" or "in/out" to describe whether procedure reads or modifies arg,
+.\" and indent is equivalent to second arg of .IP (shouldn't ever be
+.\" needed; use .AS below instead)
+.\"
+.\" .AS ?type? ?name?
+.\" Give maximum sizes of arguments for setting tab stops. Type and
+.\" name are examples of largest possible arguments that will be passed
+.\" to .AP later. If args are omitted, default tab stops are used.
+.\"
+.\" .BS
+.\" Start box enclosure. From here until next .BE, everything will be
+.\" enclosed in one large box.
+.\"
+.\" .BE
+.\" End of box enclosure.
+.\"
+.\" .CS
+.\" Begin code excerpt.
+.\"
+.\" .CE
+.\" End code excerpt.
+.\"
+.\" .VS ?version? ?br?
+.\" Begin vertical sidebar, for use in marking newly-changed parts
+.\" of man pages. The first argument is ignored and used for recording
+.\" the version when the .VS was added, so that the sidebars can be
+.\" found and removed when they reach a certain age. If another argument
+.\" is present, then a line break is forced before starting the sidebar.
+.\"
+.\" .VE
+.\" End of vertical sidebar.
+.\"
+.\" .DS
+.\" Begin an indented unfilled display.
+.\"
+.\" .DE
+.\" End of indented unfilled display.
+.\"
+.\" .SO ?manpage?
+.\" Start of list of standard options for a Tk widget. The manpage
+.\" argument defines where to look up the standard options; if
+.\" omitted, defaults to "options". The options follow on successive
+.\" lines, in three columns separated by tabs.
+.\"
+.\" .SE
+.\" End of list of standard options for a Tk widget.
+.\"
+.\" .OP cmdName dbName dbClass
+.\" Start of description of a specific option. cmdName gives the
+.\" option's name as specified in the class command, dbName gives
+.\" the option's name in the option database, and dbClass gives
+.\" the option's class in the option database.
+.\"
+.\" .UL arg1 arg2
+.\" Print arg1 underlined, then print arg2 normally.
+.\"
+.\" .QW arg1 ?arg2?
+.\" Print arg1 in quotes, then arg2 normally (for trailing punctuation).
+.\"
+.\" .PQ arg1 ?arg2?
+.\" Print an open parenthesis, arg1 in quotes, then arg2 normally
+.\" (for trailing punctuation) and then a closing parenthesis.
+.\"
+.\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages.
.if t .wh -1.3i ^B
.nr ^l \n(.l
.ad b
-'\" # Start an argument description
+.\" # Start an argument description
.de AP
.ie !"\\$4"" .TP \\$4
.el \{\
.\}
.ta \\n()Au \\n()Bu
.ie !"\\$3"" \{\
-\&\\$1 \\fI\\$2\\fP (\\$3)
+\&\\$1 \\fI\\$2\\fP (\\$3)
.\".b
.\}
.el \{\
.\}
.\}
..
-'\" # define tabbing values for .AP
+.\" # define tabbing values for .AP
.de AS
.nr )A 10n
.if !"\\$1"" .nr )A \\w'\\$1'u+3n
.nr )C \\n()Bu+\\w'(in/out)'u+2n
..
.AS Tcl_Interp Tcl_CreateInterp in/out
-'\" # BS - start boxed text
-'\" # ^y = starting y location
-'\" # ^b = 1
+.\" # BS - start boxed text
+.\" # ^y = starting y location
+.\" # ^b = 1
.de BS
.br
.mk ^y
.if n \l'\\n(.lu\(ul'
.if n .fi
..
-'\" # BE - end boxed text (draw box now)
+.\" # BE - end boxed text (draw box now)
.de BE
.nf
.ti 0
.br
.nr ^b 0
..
-'\" # VS - start vertical sidebar
-'\" # ^Y = starting y location
-'\" # ^v = 1 (for troff; for nroff this doesn't matter)
+.\" # VS - start vertical sidebar
+.\" # ^Y = starting y location
+.\" # ^v = 1 (for troff; for nroff this doesn't matter)
.de VS
.if !"\\$2"" .br
.mk ^Y
.ie n 'mc \s12\(br\s0
.el .nr ^v 1u
..
-'\" # VE - end of vertical sidebar
+.\" # VE - end of vertical sidebar
.de VE
.ie n 'mc
.el \{\
.\}
.nr ^v 0
..
-'\" # Special macro to handle page bottom: finish off current
-'\" # box/sidebar if in box/sidebar mode, then invoked standard
-'\" # page bottom macro.
+.\" # Special macro to handle page bottom: finish off current
+.\" # box/sidebar if in box/sidebar mode, then invoked standard
+.\" # page bottom macro.
.de ^B
.ev 2
'ti 0
.mk ^Y
.\}
..
-'\" # DS - begin display
+.\" # DS - begin display
.de DS
.RS
.nf
.sp
..
-'\" # DE - end display
+.\" # DE - end display
.de DE
.fi
.RE
.sp
..
-'\" # SO - start of list of standard options
+.\" # SO - start of list of standard options
.de SO
+'ie '\\$1'' .ds So \\fBoptions\\fR
+'el .ds So \\fB\\$1\\fR
.SH "STANDARD OPTIONS"
.LP
.nf
.ta 5.5c 11c
.ft B
..
-'\" # SE - end of list of standard options
+.\" # SE - end of list of standard options
.de SE
.fi
.ft R
.LP
-See the \\fBoptions\\fR manual entry for details on the standard options.
+See the \\*(So manual entry for details on the standard options.
..
-'\" # OP - start of full description for a single option
+.\" # OP - start of full description for a single option
.de OP
.LP
.nf
.fi
.IP
..
-'\" # CS - begin code excerpt
+.\" # CS - begin code excerpt
.de CS
.RS
.nf
.ta .25i .5i .75i 1i
..
-'\" # CE - end code excerpt
+.\" # CE - end code excerpt
.de CE
.fi
.RE
..
+.\" # UL - underline word
.de UL
\\$1\l'|0\(ul'\\$2
..
-.TH Tcl_ObjType 3 8.0 Tcl "Tcl Library Procedures"
+.\" # QW - apply quotation marks to word
+.de QW
+.ie '\\*(lq'"' ``\\$1''\\$2
+.\"" fix emacs highlighting
+.el \\*(lq\\$1\\*(rq\\$2
+..
+.\" # PQ - apply parens and quotation marks to word
+.de PQ
+.ie '\\*(lq'"' (``\\$1''\\$2)\\$3
+.\"" fix emacs highlighting
+.el (\\*(lq\\$1\\*(rq\\$2)\\$3
+..
+.\" # QR - quoted range
+.de QR
+.ie '\\*(lq'"' ``\\$1''\\-``\\$2''\\$3
+.\"" fix emacs highlighting
+.el \\*(lq\\$1\\*(rq\\-\\*(lq\\$2\\*(rq\\$3
+..
+.\" # MT - "empty" string
+.de MT
+.QW ""
+..
.BS
.SH NAME
-Tcl_RegisterObjType, Tcl_GetObjType, Tcl_AppendAllObjTypes, Tcl_ConvertToType \- manipulate Tcl object types
+Tcl_RegisterObjType, Tcl_GetObjType, Tcl_AppendAllObjTypes, Tcl_ConvertToType \- manipulate Tcl value types
.SH SYNOPSIS
.nf
\fB#include <tcl.h>\fR
.sp
\fBTcl_RegisterObjType\fR(\fItypePtr\fR)
.sp
-Tcl_ObjType *
+const Tcl_ObjType *
\fBTcl_GetObjType\fR(\fItypeName\fR)
.sp
int
int
\fBTcl_ConvertToType\fR(\fIinterp, objPtr, typePtr\fR)
.SH ARGUMENTS
-.AS Tcl_ObjType *typeName in
-.AP Tcl_ObjType *typePtr in
-Points to the structure containing information about the Tcl object type.
+.AS "const char" *typeName
+.AP "const Tcl_ObjType" *typePtr in
+Points to the structure containing information about the Tcl value type.
This storage must live forever,
typically by being statically allocated.
-.AP "CONST char" *typeName in
-The name of a Tcl object type that \fBTcl_GetObjType\fR should look up.
+.AP "const char" *typeName in
+The name of a Tcl value type that \fBTcl_GetObjType\fR should look up.
.AP Tcl_Interp *interp in
Interpreter to use for error reporting.
.AP Tcl_Obj *objPtr in
-For \fBTcl_AppendAllObjTypes\fR, this points to the object onto which
-it appends the name of each object type as a list element.
-For \fBTcl_ConvertToType\fR, this points to an object that
+For \fBTcl_AppendAllObjTypes\fR, this points to the value onto which
+it appends the name of each value type as a list element.
+For \fBTcl_ConvertToType\fR, this points to a value that
must have been the result of a previous call to \fBTcl_NewObj\fR.
.BE
.SH DESCRIPTION
.PP
-The procedures in this man page manage Tcl object types.
-The are used to register new object types,
-look up types,
+The procedures in this man page manage Tcl value types (sometimes
+referred to as object types or \fBTcl_ObjType\fRs for historical reasons).
+They are used to register new value types, look up types,
and force conversions from one type to another.
.PP
-\fBTcl_RegisterObjType\fR registers a new Tcl object type
-in the table of all object types supported by Tcl.
+\fBTcl_RegisterObjType\fR registers a new Tcl value type
+in the table of all value types that \fBTcl_GetObjType\fR
+can look up by name. There are other value types supported by Tcl
+as well, which Tcl chooses not to register. Extensions can likewise
+choose to register the value types they create or not.
The argument \fItypePtr\fR points to a Tcl_ObjType structure that
describes the new type by giving its name
and by supplying pointers to four procedures
The Tcl_ObjType structure is described
in the section \fBTHE TCL_OBJTYPE STRUCTURE\fR below.
.PP
-\fBTcl_GetObjType\fR returns a pointer to the Tcl_ObjType
+\fBTcl_GetObjType\fR returns a pointer to the registered Tcl_ObjType
with name \fItypeName\fR.
It returns NULL if no type with that name is registered.
.PP
-\fBTcl_AppendAllObjTypes\fR appends the name of each object type
-as a list element onto the Tcl object referenced by \fIobjPtr\fR.
+\fBTcl_AppendAllObjTypes\fR appends the name of each registered value type
+as a list element onto the Tcl value referenced by \fIobjPtr\fR.
The return value is \fBTCL_OK\fR unless there was an error
-converting \fIobjPtr\fR to a list object;
+converting \fIobjPtr\fR to a list value;
in that case \fBTCL_ERROR\fR is returned.
.PP
-\fBTcl_ConvertToType\fR converts an object from one type to another
+\fBTcl_ConvertToType\fR converts a value from one type to another
if possible.
It creates a new internal representation for \fIobjPtr\fR
appropriate for the target type \fItypePtr\fR
-and sets its \fItypePtr\fR member to that type.
+and sets its \fItypePtr\fR member as determined by calling the
+\fItypePtr->setFromAnyProc\fR routine.
Any internal representation for \fIobjPtr\fR's old type is freed.
If an error occurs during conversion, it returns \fBTCL_ERROR\fR
-and leaves an error message in the result object for \fIinterp\fR
+and leaves an error message in the result value for \fIinterp\fR
unless \fIinterp\fR is NULL.
Otherwise, it returns \fBTCL_OK\fR.
Passing a NULL \fIinterp\fR allows this procedure to be used
as a test whether the conversion can be done (and in fact was done).
-
+.VS 8.5
+.PP
+In many cases, the \fItypePtr->setFromAnyProc\fR routine will
+set \fIobjPtr->typePtr\fR to the argument value \fItypePtr\fR,
+but that is no longer guaranteed. The \fIsetFromAnyProc\fR is
+free to set the internal representation for \fIobjPtr\fR to make
+use of another related Tcl_ObjType, if it sees fit.
+.VE 8.5
.SH "THE TCL_OBJTYPE STRUCTURE"
.PP
-Extension writers can define new object types by defining four
-procedures,
-initializing a Tcl_ObjType structure to describe the type,
-and calling \fBTcl_RegisterObjType\fR.
+Extension writers can define new value types by defining four
+procedures and
+initializing a Tcl_ObjType structure to describe the type.
+Extension writers may also pass a pointer to their Tcl_ObjType
+structure to \fBTcl_RegisterObjType\fR if they wish to permit
+other extensions to look up their Tcl_ObjType by name with
+the \fBTcl_GetObjType\fR routine.
The \fBTcl_ObjType\fR structure is defined as follows:
+.PP
.CS
typedef struct Tcl_ObjType {
- char *\fIname\fR;
- Tcl_FreeInternalRepProc *\fIfreeIntRepProc\fR;
- Tcl_DupInternalRepProc *\fIdupIntRepProc\fR;
- Tcl_UpdateStringProc *\fIupdateStringProc\fR;
- Tcl_SetFromAnyProc *\fIsetFromAnyProc\fR;
-} Tcl_ObjType;
+ const char *\fIname\fR;
+ Tcl_FreeInternalRepProc *\fIfreeIntRepProc\fR;
+ Tcl_DupInternalRepProc *\fIdupIntRepProc\fR;
+ Tcl_UpdateStringProc *\fIupdateStringProc\fR;
+ Tcl_SetFromAnyProc *\fIsetFromAnyProc\fR;
+} \fBTcl_ObjType\fR;
.CE
+.SS "THE NAME FIELD"
.PP
The \fIname\fR member describes the name of the type, e.g. \fBint\fR.
-Extension writers can look up an object type using its name
-with the \fBTcl_GetObjType\fR procedure.
+When a type is registered, this is the name used by callers
+of \fBTcl_GetObjType\fR to lookup the type. For unregistered
+types, the \fIname\fR field is primarily of value for debugging.
The remaining four members are pointers to procedures
-called by the generic Tcl object code:
+called by the generic Tcl value code:
+.SS "THE SETFROMANYPROC FIELD"
.PP
The \fIsetFromAnyProc\fR member contains the address of a function
called to create a valid internal representation
-from an object's string representation.
+from a value's string representation.
+.PP
.CS
-typedef int (Tcl_SetFromAnyProc) (Tcl_Interp *\fIinterp\fR, Tcl_Obj *\fIobjPtr\fR);
+typedef int \fBTcl_SetFromAnyProc\fR(
+ Tcl_Interp *\fIinterp\fR,
+ Tcl_Obj *\fIobjPtr\fR);
.CE
-If an internal representation can't be created from the string,
+.PP
+If an internal representation cannot be created from the string,
it returns \fBTCL_ERROR\fR and puts a message
-describing the error in the result object for \fIinterp\fR
+describing the error in the result value for \fIinterp\fR
unless \fIinterp\fR is NULL.
If \fIsetFromAnyProc\fR is successful,
it stores the new internal representation,
sets \fIobjPtr\fR's \fItypePtr\fR member to point to
-\fIsetFromAnyProc\fR's \fBTcl_ObjType\fR, and returns \fBTCL_OK\fR.
+the \fBTcl_ObjType\fR struct corresponding to the new
+internal representation, and returns \fBTCL_OK\fR.
Before setting the new internal representation,
the \fIsetFromAnyProc\fR must free any internal representation
of \fIobjPtr\fR's old type;
it does this by calling the old type's \fIfreeIntRepProc\fR
if it is not NULL.
-As an example, the \fIsetFromAnyProc\fR for the builtin Tcl integer type
+.PP
+As an example, the \fIsetFromAnyProc\fR for the built-in Tcl list type
gets an up-to-date string representation for \fIobjPtr\fR
by calling \fBTcl_GetStringFromObj\fR.
-It parses the string to obtain an integer and,
-if this succeeds,
-stores the integer in \fIobjPtr\fR's internal representation
-and sets \fIobjPtr\fR's \fItypePtr\fR member to point to the integer type's
+It parses the string to verify it is in a valid list format and
+to obtain each element value in the list, and, if this succeeds,
+stores the list elements in \fIobjPtr\fR's internal representation
+and sets \fIobjPtr\fR's \fItypePtr\fR member to point to the list type's
Tcl_ObjType structure.
+.PP
Do not release \fIobjPtr\fR's old internal representation unless you
replace it with a new one or reset the \fItypePtr\fR member to NULL.
.PP
+The \fIsetFromAnyProc\fR member may be set to NULL, if the routines
+making use of the internal representation have no need to derive that
+internal representation from an arbitrary string value. However, in
+this case, passing a pointer to the type to \fBTcl_ConvertToType\fR will
+lead to a panic, so to avoid this possibility, the type
+should \fInot\fR be registered.
+.SS "THE UPDATESTRINGPROC FIELD"
+.PP
The \fIupdateStringProc\fR member contains the address of a function
called to create a valid string representation
-from an object's internal representation.
+from a value's internal representation.
+.PP
.CS
-typedef void (Tcl_UpdateStringProc) (Tcl_Obj *\fIobjPtr\fR);
+typedef void \fBTcl_UpdateStringProc\fR(
+ Tcl_Obj *\fIobjPtr\fR);
.CE
+.PP
\fIobjPtr\fR's \fIbytes\fR member is always NULL when it is called.
It must always set \fIbytes\fR non-NULL before returning.
We require the string representation's byte array
-to have a null after the last byte, at offset \fIlength\fR;
-this allows string representations that do not contain null bytes
+to have a null after the last byte, at offset \fIlength\fR,
+and to have no null bytes before that; this allows string representations
to be treated as conventional null character-terminated C strings.
+These restrictions are easily met by using Tcl's internal UTF encoding
+for the string representation, same as one would do for other
+Tcl routines accepting string values as arguments.
Storage for the byte array must be allocated in the heap by \fBTcl_Alloc\fR
or \fBckalloc\fR. Note that \fIupdateStringProc\fRs must allocate
enough storage for the string's bytes and the terminating null byte.
-The \fIupdateStringProc\fR for Tcl's builtin list type, for example,
-builds an array of strings for each element object
-and then calls \fBTcl_Merge\fR
-to construct a string with proper Tcl list structure.
-It stores this string as the list object's string representation.
+.PP
+The \fIupdateStringProc\fR for Tcl's built-in double type, for example,
+calls Tcl_PrintDouble to write to a buffer of size TCL_DOUBLE_SPACE,
+then allocates and copies the string representation to just enough
+space to hold it. A pointer to the allocated space is stored in
+the \fIbytes\fR member.
+.PP
+The \fIupdateStringProc\fR member may be set to NULL, if the routines
+making use of the internal representation are written so that the
+string representation is never invalidated. Failure to meet this
+obligation will lead to panics or crashes when \fBTcl_GetStringFromObj\fR
+or other similar routines ask for the string representation.
+.SS "THE DUPINTREPPROC FIELD"
.PP
The \fIdupIntRepProc\fR member contains the address of a function
-called to copy an internal representation from one object to another.
+called to copy an internal representation from one value to another.
+.PP
.CS
-typedef void (Tcl_DupInternalRepProc) (Tcl_Obj *\fIsrcPtr\fR, Tcl_Obj *\fIdupPtr\fR);
+typedef void \fBTcl_DupInternalRepProc\fR(
+ Tcl_Obj *\fIsrcPtr\fR,
+ Tcl_Obj *\fIdupPtr\fR);
.CE
+.PP
\fIdupPtr\fR's internal representation is made a copy of \fIsrcPtr\fR's
internal representation.
Before the call,
\fIsrcPtr\fR's internal representation is valid and \fIdupPtr\fR's is not.
-\fIsrcPtr\fR's object type determines what
+\fIsrcPtr\fR's value type determines what
copying its internal representation means.
+.PP
For example, the \fIdupIntRepProc\fR for the Tcl integer type
simply copies an integer.
-The builtin list type's \fIdupIntRepProc\fR
-allocates a new array that points at the original element objects;
-the elements are shared between the two lists
-(and their reference counts are incremented to reflect the new references).
+The built-in list type's \fIdupIntRepProc\fR uses a far more
+sophisticated scheme to continue sharing storage as much as it
+reasonably can.
+.SS "THE FREEINTREPPROC FIELD"
.PP
The \fIfreeIntRepProc\fR member contains the address of a function
-that is called when an object is freed.
+that is called when a value is freed.
+.PP
.CS
-typedef void (Tcl_FreeInternalRepProc) (Tcl_Obj *\fIobjPtr\fR);
+typedef void \fBTcl_FreeInternalRepProc\fR(
+ Tcl_Obj *\fIobjPtr\fR);
.CE
+.PP
The \fIfreeIntRepProc\fR function can deallocate the storage
-for the object's internal representation
-and do other type-specific processing necessary when an object is freed.
-For example, Tcl list objects have an \fIinternalRep.otherValuePtr\fR
-that points to an array of pointers to each element in the list.
-The list type's \fIfreeIntRepProc\fR decrements
-the reference count for each element object
-(since the list will no longer refer to those objects),
-then deallocates the storage for the array of pointers.
+for the value's internal representation
+and do other type-specific processing necessary when a value is freed.
+.PP
+For example, the list type's \fIfreeIntRepProc\fR respects
+the storage sharing scheme established by the \fIdupIntRepProc\fR
+so that it only frees storage when the last value sharing it
+is being freed.
+.PP
The \fIfreeIntRepProc\fR member can be set to NULL
to indicate that the internal representation does not require freeing.
-
+The \fIfreeIntRepProc\fR implementation must not access the
+\fIbytes\fR member of the value, since Tcl makes its own internal
+uses of that field during value deletion. The defined tasks for
+the \fIfreeIntRepProc\fR have no need to consult the \fIbytes\fR
+member.
.SH "SEE ALSO"
-Tcl_NewObj, Tcl_DecrRefCount, Tcl_IncrRefCount
-
+Tcl_NewObj(3), Tcl_DecrRefCount(3), Tcl_IncrRefCount(3)
.SH KEYWORDS
-internal representation, object, object type, string representation, type conversion
+internal representation, value, value type, string representation, type conversion
OSDN Git Service
