plucky (3) Tcl_HideCommand.3tcl.gz

Provided by: tcl9.0-doc_9.0.1+dfsg-1_all bug

NAME

       Tcl_IsSafe,    Tcl_CreateChild,    Tcl_GetChild,   Tcl_GetParent,   Tcl_GetInterpPath,   Tcl_CreateAlias,
       Tcl_CreateAliasObj,  Tcl_GetAliasObj,  Tcl_ExposeCommand,   Tcl_HideCommand   -   manage   multiple   Tcl
       interpreters, aliases and hidden commands

SYNOPSIS

       #include <tcl.h>

       int
       Tcl_IsSafe(interp)

       Tcl_Interp *
       Tcl_CreateChild(interp, name, isSafe)

       Tcl_Interp *
       Tcl_GetChild(interp, name)

       Tcl_Interp *
       Tcl_GetParent(interp)

       int
       Tcl_GetInterpPath(interp, childInterp)

       int
       Tcl_CreateAlias(childInterp, childCmd, targetInterp, targetCmd,
                       argc, argv)

       int
       Tcl_CreateAliasObj(childInterp, childCmd, targetInterp, targetCmd,
                          objc, objv)

       int
       Tcl_GetAliasObj(interp, childCmd, targetInterpPtr, targetCmdPtr,
                       objcPtr, objvPtr)

       int
       Tcl_ExposeCommand(interp, hiddenCmdName, cmdName)

       int
       Tcl_HideCommand(interp, cmdName, hiddenCmdName)

ARGUMENTS

       Tcl_Interp *interp (in)                           Interpreter in which to execute the specified command.

       const char *name (in)                             Name of child interpreter to create or manipulate.

       int isSafe (in)                                   If  non-zero,  a  “safe”  child  that  is  suitable for
                                                         running untrusted code is created, otherwise a  trusted
                                                         child is created.

       Tcl_Interp *childInterp (in)                      Interpreter  to use for creating the source command for
                                                         an alias (see below).

       const char *childCmd (in)                         Name of source command for alias.

       Tcl_Interp *targetInterp (in)                     Interpreter that contains the  target  command  for  an
                                                         alias.

       const char *targetCmd (in)                        Name of target command for alias in targetInterp.

       Tcl_Size argc (in)                                Count  of  additional  arguments  to  pass to the alias
                                                         command.

       const char *const *argv (in)                      Vector of strings, the additional arguments to pass  to
                                                         the  alias  command.   This  storage  is  owned  by the
                                                         caller.

       Tcl_Size objc (in)                                Count of additional value  arguments  to  pass  to  the
                                                         aliased command.

       Tcl_Obj **objv (in)                               Vector  of  Tcl_Obj  structures,  the  additional value
                                                         arguments to pass to the aliased command.  This storage
                                                         is owned by the caller.

       Tcl_Interp **targetInterpPtr (in)                 Pointer  to  location  to  store  the  address  of  the
                                                         interpreter where a target command is  defined  for  an
                                                         alias.

       const char **targetCmdPtr (out)                   Pointer to location to store the address of the name of
                                                         the target command for an alias.

       Tcl_Size | int *objcPtr (out)                     Pointer to location to store count of additional  value
                                                         arguments to be passed to the alias. The location is in
                                                         storage owned  by  the  caller.   If  it  points  to  a
                                                         variable which type is not Tcl_Size, a compiler warning
                                                         will be generated. If your extensions is compiled  with
                                                         -DTCL_8_API,  this  function  will return TCL_ERROR for
                                                         aliases  with  more  than  INT_MAX   value   arguments,
                                                         otherwise expect it to crash

       Tcl_Obj ***objvPtr (out)                          Pointer  to  location  to  store  a  vector  of Tcl_Obj
                                                         structures, the additional  arguments  to  pass  to  an
                                                         alias  command. The location is in storage owned by the
                                                         caller, the vector of Tcl_Obj structures  is  owned  by
                                                         the called function.

       const char *cmdName (in)                          Name of an exposed command to hide or create.

       const char *hiddenCmdName (in)                    Name  under  which  a hidden command is stored and with
                                                         which it can be exposed or invoked.
________________________________________________________________________________________________________________

DESCRIPTION

       These procedures are intended for access to the multiple interpreter facility  from  inside  C  programs.
       They enable managing multiple interpreters in a hierarchical relationship, and the management of aliases,
       commands that when invoked in one interpreter execute a command in another interpreter. The return  value
       for  those procedures that return an int is either TCL_OK or TCL_ERROR. If TCL_ERROR is returned then the
       interpreter's result contains an error message.

       Tcl_CreateChild creates a new interpreter as a child of interp.  It also creates a  child  command  named
       name in interp which allows interp to manipulate the new child.  If isSafe is zero, the command creates a
       trusted child in which Tcl code has access to all the Tcl commands.  If it is 1, the  command  creates  a
       “safe”  child  in  which  Tcl  code has access only to set of Tcl commands defined as “Safe Tcl”; see the
       manual entry for the Tcl interp command for details.  If  the  creation  of  the  new  child  interpreter
       failed, NULL is returned.

       Tcl_IsSafe  returns  1  if interp is “safe” (was created with the TCL_SAFE_INTERPRETER flag specified), 0
       otherwise.

       Tcl_GetChild returns a pointer to a child interpreter of interp. The child interpreter is  identified  by
       name.  If no such child interpreter exists, NULL is returned.

       Tcl_GetParent  returns  a  pointer  to the parent interpreter of interp. If interp has no parent (it is a
       top-level interpreter) then NULL is returned.

       Tcl_GetInterpPath stores in the result of interp  the  relative  path  between  interp  and  childInterp;
       childInterp  must  be  a  child  of  interp.  If the computation of the relative path succeeds, TCL_OK is
       returned, else TCL_ERROR is returned and an error message is stored as the result of interp.

       Tcl_CreateAlias creates a command named childCmd in childInterp that when invoked, will cause the command
       targetCmd  to  be  invoked  in targetInterp. The arguments specified by the strings contained in argv are
       always prepended to any arguments supplied in the invocation of childCmd and passed to  targetCmd.   This
       operation returns TCL_OK if it succeeds, or TCL_ERROR if it fails; in that case, an error message is left
       in the value result of childInterp.  Note that there are no restrictions on the ancestry relationship (as
       created  by  Tcl_CreateChild)  between  childInterp  and  targetInterp. Any two interpreters can be used,
       without any restrictions on how they are related.

       Tcl_CreateAliasObj is similar to Tcl_CreateAlias except that it takes a  vector  of  values  to  pass  as
       additional arguments instead of a vector of strings.

       Tcl_GetAliasObj  returns  information in the form of a pointer to a vector of Tcl_Obj structures about an
       alias aliasName in interp. Any of the result fields can be NULL, in which case the corresponding datum is
       not  returned.  If  a  result field is non-NULL, the address indicated is set to the corresponding datum.
       For example, if targetCmdPtr is non-NULL it is set to a pointer to the string containing the name of  the
       target command.

       Tcl_ExposeCommand  moves  the  command  named hiddenCmdName from the set of hidden commands to the set of
       exposed commands, putting it under the name cmdName.  HiddenCmdName must  be  the  name  of  an  existing
       hidden  command,  or  the  operation  will  return  TCL_ERROR and leave an error message as the result of
       interp.  If an exposed command named cmdName already exists, the operation returns TCL_ERROR  and  leaves
       an error message as the result of interp.  If the operation succeeds, it returns TCL_OK.  After executing
       this command, attempts to use cmdName in any script evaluation mechanism will again succeed.

       Tcl_HideCommand moves the command named cmdName from the set of exposed commands to  the  set  of  hidden
       commands,  under the name hiddenCmdName.  CmdName must be the name of an existing exposed command, or the
       operation will return TCL_ERROR and leave an error message as  the  result  of  interp.   Currently  both
       cmdName  and  hiddenCmdName must not contain namespace qualifiers, or the operation will return TCL_ERROR
       and leave an error message as the result of interp.   The  CmdName  will  be  looked  up  in  the  global
       namespace,  and  not  relative  to the current namespace, even if the current namespace is not the global
       one.  If a hidden command whose  name  is  hiddenCmdName  already  exists,  the  operation  also  returns
       TCL_ERROR  and  an  error message is left as the result of interp.  If the operation succeeds, it returns
       TCL_OK.  After executing this command, attempts to use cmdName in any script  evaluation  mechanism  will
       fail.

       For a description of the Tcl interface to multiple interpreters, see interp(3tcl).

REFERENCE COUNT MANAGEMENT

       Tcl_CreateAliasObj  increments  the  reference counts of the values in its objv argument. (That reference
       lasts the same length of time as the owning alias.)

       Tcl_GetAliasObj returns (via its objvPtr argument) a pointer to values that it holds a reference to.

SEE ALSO

       interp(3tcl)

KEYWORDS

       alias, command, exposed commands, hidden commands, interpreter, invoke, parent, child