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diff --git a/tcl/doc/CrtObjCmd.3 b/tcl/doc/CrtObjCmd.3 new file mode 100644 index 00000000000..74ec90bf6c0 --- /dev/null +++ b/tcl/doc/CrtObjCmd.3 @@ -0,0 +1,248 @@ +'\" +'\" Copyright (c) 1996-1997 Sun Microsystems, Inc. +'\" +'\" See the file "license.terms" for information on usage and redistribution +'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. +'\" +'\" RCS: @(#) $Id$ +'\" +.so man.macros +.TH Tcl_CreateObjCommand 3 8.0 Tcl "Tcl Library Procedures" +.BS +.SH NAME +Tcl_CreateObjCommand, Tcl_DeleteCommand, Tcl_DeleteCommandFromToken, Tcl_GetCommandInfo, Tcl_SetCommandInfo, Tcl_GetCommandName \- implement new commands in C +.SH SYNOPSIS +.nf +\fB#include <tcl.h>\fR +.sp +Tcl_Command +\fBTcl_CreateObjCommand\fR(\fIinterp, cmdName, proc, clientData, deleteProc\fR) +.sp +int +\fBTcl_DeleteCommand\fR(\fIinterp, cmdName\fR) +.sp +int +\fBTcl_DeleteCommandFromToken\fR(\fIinterp, token\fR) +.sp +int +\fBTcl_GetCommandInfo\fR(\fIinterp, cmdName, infoPtr\fR) +.sp +int +\fBTcl_SetCommandInfo\fR(\fIinterp, cmdName, infoPtr\fR) +.sp +char * +\fBTcl_GetCommandName\fR(\fIinterp, token\fR) +.SH ARGUMENTS +.AS Tcl_ObjCmdProc *deleteProc in/out +.AP Tcl_Interp *interp in +Interpreter in which to create a new command or that contains a command. +.AP char *cmdName in +Name of command. +.AP Tcl_ObjCmdProc *proc in +Implementation of the new command: \fIproc\fR will be called whenever +\fIcmdName\fR is invoked as a command. +.AP ClientData clientData in +Arbitrary one-word value to pass to \fIproc\fR and \fIdeleteProc\fR. +.AP Tcl_CmdDeleteProc *deleteProc in +Procedure to call before \fIcmdName\fR is deleted from the interpreter; +allows for command-specific cleanup. If NULL, then no procedure is +called before the command is deleted. +.AP Tcl_Command token in +Token for command, returned by previous call to \fBTcl_CreateObjCommand\fR. +The command must not have been deleted. +.AP Tcl_CmdInfo *infoPtr in/out +Pointer to structure containing various information about a +Tcl command. +.BE +.SH DESCRIPTION +.PP +\fBTcl_CreateObjCommand\fR defines a new command in \fIinterp\fR +and associates it with procedure \fIproc\fR +such that whenever \fIname\fR is +invoked as a Tcl command (e.g., via a call to \fBTcl_EvalObj\fR) +the Tcl interpreter will call \fIproc\fR to process the command. +.PP +\fBTcl_CreateObjCommand\fR will delete any command \fIname\fR +already associated with the interpreter. +It returns a token that may be used to refer +to the command in subsequent calls to \fBTcl_GetCommandName\fR. +If \fIname\fR contains any \fB::\fR namespace qualifiers, +then the command is added to the specified namespace; +otherwise the command is added to the global namespace. +If \fBTcl_CreateObjCommand\fR is called for an interpreter that is in +the process of being deleted, then it does not create a new command +and it returns NULL. +\fIproc\fR should have arguments and result that match the type +\fBTcl_ObjCmdProc\fR: +.CS +typedef int Tcl_ObjCmdProc( + ClientData \fIclientData\fR, + Tcl_Interp *\fIinterp\fR, + int \fIobjc\fR, +.VS + Tcl_Obj *CONST \fIobjv\fR[]); +.CE +When \fIproc\fR is invoked, the \fIclientData\fR and \fIinterp\fR parameters +will be copies of the \fIclientData\fR and \fIinterp\fR arguments given to +\fBTcl_CreateObjCommand\fR. Typically, \fIclientData\fR points to an +application-specific data structure that describes what to do when the +command procedure is invoked. \fIObjc\fR and \fIobjv\fR describe the +arguments to the command, \fIobjc\fR giving the number of argument objects +(including the command name) and \fIobjv\fR giving the values of the +arguments. The \fIobjv\fR array will contain \fIobjc\fR values, pointing to +the argument objects. Unlike \fIargv\fR[\fIargv\fR] used in a +string-based command procedure, \fIobjv\fR[\fIobjc\fR] will not contain NULL. +.PP +Additionally, when \fIproc\fR is invoked, it must not modify the contents +of the \fIobjv\fR array by assigning new pointer values to any element of the +array (for example, \fIobjv\fR[\fB2\fR] = \fBNULL\fR) because this will +cause memory to be lost and the runtime stack to be corrupted. The +\fBCONST\fR in the declaration of \fIobjv\fR will cause ANSI-compliant +compilers to report any such attempted assignment as an error. However, +it is acceptable to modify the internal representation of any individual +object argument. For instance, the user may call +\fBTcl_GetIntFromObject\fR on \fIobjv\fR[\fB2\fR] to obtain the integer +representation of that object; that call may change the type of the object +that \fIobjv\fR[\fB2\fR] points at, but will not change where +\fIobjv\fR[\fB2\fR] points. +.VE +.PP +\fIproc\fR must return an integer code that is either \fBTCL_OK\fR, +\fBTCL_ERROR\fR, \fBTCL_RETURN\fR, \fBTCL_BREAK\fR, or \fBTCL_CONTINUE\fR. +See the Tcl overview man page +for details on what these codes mean. Most normal commands will only +return \fBTCL_OK\fR or \fBTCL_ERROR\fR. +In addition, if \fIproc\fR needs to return a non-empty result, +it can call \fBTcl_SetObjResult\fR to set the interpreter's result. +In the case of a \fBTCL_OK\fR return code this gives the result +of the command, +and in the case of \fBTCL_ERROR\fR this gives an error message. +Before invoking a command procedure, +\fBTcl_EvalObj\fR sets interpreter's result to +point to an object representing an empty string, so simple +commands can return an empty result by doing nothing at all. +.PP +The contents of the \fIobjv\fR array belong to Tcl and are not +guaranteed to persist once \fIproc\fR returns: \fIproc\fR should +not modify them. +Call \fBTcl_SetObjResult\fR if you want +to return something from the \fIobjv\fR array. +.PP +\fIDeleteProc\fR will be invoked when (if) \fIname\fR is deleted. +This can occur through a call to \fBTcl_DeleteCommand\fR, +\fBTcl_DeleteCommandFromToken\fR, or \fBTcl_DeleteInterp\fR, +or by replacing \fIname\fR in another call to \fBTcl_CreateObjCommand\fR. +\fIDeleteProc\fR is invoked before the command is deleted, and gives the +application an opportunity to release any structures associated +with the command. \fIDeleteProc\fR should have arguments and +result that match the type \fBTcl_CmdDeleteProc\fR: +.CS +typedef void Tcl_CmdDeleteProc(ClientData \fIclientData\fR); +.CE +The \fIclientData\fR argument will be the same as the \fIclientData\fR +argument passed to \fBTcl_CreateObjCommand\fR. +.PP +\fBTcl_DeleteCommand\fR deletes a command from a command interpreter. +Once the call completes, attempts to invoke \fIcmdName\fR in +\fIinterp\fR will result in errors. +If \fIcmdName\fR isn't bound as a command in \fIinterp\fR then +\fBTcl_DeleteCommand\fR does nothing and returns -1; otherwise +it returns 0. +There are no restrictions on \fIcmdName\fR: it may refer to +a built-in command, an application-specific command, or a Tcl procedure. +If \fIname\fR contains any \fB::\fR namespace qualifiers, +the command is deleted from the specified namespace. +.PP +Given a token returned by \fBTcl_CreateObjCommand\fR, +\fBTcl_DeleteCommandFromToken\fR deletes the command +from a command interpreter. +It will delete a command even if that command has been renamed. +Once the call completes, attempts to invoke the command in +\fIinterp\fR will result in errors. +If the command corresponding to \fItoken\fR +has already been deleted from \fIinterp\fR then +\fBTcl_DeleteCommand\fR does nothing and returns -1; +otherwise it returns 0. +.PP +\fBTcl_GetCommandInfo\fR checks to see whether its \fIcmdName\fR argument +exists as a command in \fIinterp\fR. +\fIcmdName\fR may include \fB::\fR namespace qualifiers +to identify a command in a particular namespace. +If the command is not found, then it returns 0. +Otherwise it places information about the command +in the \fBTcl_CmdInfo\fR structure +pointed to by \fIinfoPtr\fR and returns 1. +A \fBTcl_CmdInfo\fR structure has the following fields: +.CS +typedef struct Tcl_CmdInfo { + int isNativeObjectProc; + Tcl_ObjCmdProc *objProc; + ClientData objClientData; + Tcl_CmdProc *proc; + ClientData clientData; + Tcl_CmdDeleteProc *deleteProc; + ClientData deleteData; + Tcl_Namespace *namespacePtr; +} Tcl_CmdInfo; +.CE +The \fIisNativeObjectProc\fR field has the value 1 +if \fBTcl_CreateObjCommand\fR was called to register the command; +it is 0 if only \fBTcl_CreateCommand\fR was called. +It allows a program to determine whether it is faster to +call \fIobjProc\fR or \fIproc\fR: +\fIobjProc\fR is normally faster +if \fIisNativeObjectProc\fR has the value 1. +The fields \fIobjProc\fR and \fIobjClientData\fR +have the same meaning as the \fIproc\fR and \fIclientData\fR +arguments to \fBTcl_CreateObjCommand\fR; +they hold information about the object-based command procedure +that the Tcl interpreter calls to implement the command. +The fields \fIproc\fR and \fIclientData\fR +hold information about the string-based command procedure +that implements the command. +If \fBTcl_CreateCommand\fR was called for this command, +this is the procedure passed to it; +otherwise, this is a compatibility procedure +registered by \fBTcl_CreateObjCommand\fR +that simply calls the command's +object-based procedure after converting its string arguments to Tcl objects. +The field \fIdeleteData\fR is the ClientData value +to pass to \fIdeleteProc\fR; it is normally the same as +\fIclientData\fR but may be set independently using the +\fBTcl_SetCommandInfo\fR procedure. +The field \fInamespacePtr\fR holds a pointer to the +Tcl_Namespace that contains the command. +.PP +\fBTcl_SetCommandInfo\fR is used to modify the procedures and +ClientData values associated with a command. +Its \fIcmdName\fR argument is the name of a command in \fIinterp\fR. +\fIcmdName\fR may include \fB::\fR namespace qualifiers +to identify a command in a particular namespace. +If this command does not exist then \fBTcl_SetCommandInfo\fR returns 0. +Otherwise, it copies the information from \fI*infoPtr\fR to +Tcl's internal structure for the command and returns 1. +Note that this procedure allows the ClientData for a command's +deletion procedure to be given a different value than the ClientData +for its command procedure. +Note that \fBTcl_SetCmdInfo\fR will not change a command's namespace; +you must use \fBTcl_RenameCommand\fR to do that. +.PP +\fBTcl_GetCommandName\fR provides a mechanism for tracking commands +that have been renamed. +Given a token returned by \fBTcl_CreateObjCommand\fR +when the command was created, \fBTcl_GetCommandName\fR returns the +string name of the command. If the command has been renamed since it +was created, then \fBTcl_GetCommandName\fR returns the current name. +This name does not include any \fB::\fR namespace qualifiers. +The command corresponding to \fItoken\fR must not have been deleted. +The string returned by \fBTcl_GetCommandName\fR is in dynamic memory +owned by Tcl and is only guaranteed to retain its value as long as the +command isn't deleted or renamed; callers should copy the string if +they need to keep it for a long time. +.PP + +.SH "SEE ALSO" +Tcl_CreateCommand, Tcl_ResetResult, Tcl_SetObjResult + +.SH KEYWORDS +bind, command, create, delete, namespace, object |