Tcl_CreateAlias(3tcl) Tcl Library Procedures Tcl_CreateAlias(3tcl)
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NAME
Tcl_IsSafe, Tcl_MakeSafe, Tcl_CreateChild, Tcl_CreateSlave,
Tcl_GetChild, Tcl_GetSlave, Tcl_GetParent, Tcl_GetMaster, Tcl_Get-
InterpPath, Tcl_CreateAlias, Tcl_CreateAliasObj, Tcl_GetAlias,
Tcl_GetAliasObj, Tcl_ExposeCommand, Tcl_HideCommand - manage multiple
Tcl interpreters, aliases and hidden commands
SYNOPSIS
#include <tcl.h>
int
Tcl_IsSafe(interp)
int
Tcl_MakeSafe(interp)
Tcl_Interp * │
Tcl_CreateChild(interp, name, isSafe) │
Tcl_Interp *
Tcl_CreateSlave(interp, name, isSafe)
Tcl_Interp * │
Tcl_GetChild(interp, name) │
Tcl_Interp *
Tcl_GetSlave(interp, name)
Tcl_Interp * │
Tcl_GetParent(interp) │
Tcl_Interp *
Tcl_GetMaster(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_GetAlias(interp, childCmd, targetInterpPtr, targetCmdPtr,
argcPtr, argvPtr)
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 speci-
fied command.
const char *name (in) Name of child inter-
preter to create or
manipulate.
int isSafe (in) If non-zero, a “safe”
child that is suit-
able for running un-
trusted code is cre-
ated, otherwise a
trusted child is cre-
ated.
Tcl_Interp *childInterp (in) Interpreter to use
for creating the
source command for an
alias (see below).
const char *childCmd (in) Name of source com-
mand for alias.
Tcl_Interp *targetInterp (in) Interpreter that con-
tains the target com-
mand for an alias.
const char *targetCmd (in) Name of target com-
mand for alias in
targetInterp.
int argc (in) Count of additional
arguments to pass to
the alias command.
const char *const *argv (in) Vector of strings,
the additional argu-
ments to pass to the
alias command. This
storage is owned by
the caller.
int objc (in) Count of additional
value arguments to
pass to the aliased
command.
Tcl_Obj **objv (in) Vector of Tcl_Obj
structures, the addi-
tional value argu-
ments 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 com-
mand 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.
int *argcPtr (out) Pointer to location
to store count of ad-
ditional arguments to
be passed to the
alias. The location
is in storage owned
by the caller.
const char ***argvPtr (out) Pointer to location
to store a vector of
strings, the addi-
tional arguments to
pass to an alias. The
location is in stor-
age owned by the
caller, the vector of
strings is owned by
the called function.
int *objcPtr (out) Pointer to location
to store count of ad-
ditional value argu-
ments to be passed to
the alias. The loca-
tion is in storage
owned by the caller.
Tcl_Obj ***objvPtr (out) Pointer to location
to store a vector of
Tcl_Obj structures,
the additional argu-
ments to pass to an
alias command. The
location is in stor-
age 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.
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DESCRIPTION
These procedures are intended for access to the multiple interpreter
facility from inside C programs. They enable managing multiple inter-
preters in a hierarchical relationship, and the management of aliases,
commands that when invoked in one interpreter execute a command in an-
other 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_CreateSlave creates a new interpreter as a child of interp. It
also creates a child command named childName in interp which allows in-
terp to manipulate the new child. If isSafe is zero, the command cre-
ates a trusted child in which Tcl code has access to all the Tcl com-
mands. 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 cre-
ation of the new child interpreter failed, NULL is returned.
Tcl_CreateChild is a synonym for Tcl_CreateSlave. │
Tcl_IsSafe returns 1 if interp is “safe” (was created with the
TCL_SAFE_INTERPRETER flag specified), 0 otherwise.
Tcl_MakeSafe marks interp as “safe”, so that future calls to Tcl_IsSafe
will return 1. It also removes all known potentially-unsafe core func-
tionality (both commands and variables) from interp. However, it can-
not know what parts of an extension or application are safe and does
not make any attempt to remove those parts, so safety is not guaranteed
after calling Tcl_MakeSafe. Callers will want to take care with their
use of Tcl_MakeSafe to avoid false claims of safety. For many situa-
tions, Tcl_CreateSlave may be a better choice, since it creates inter-
preters in a known-safe state.
Tcl_GetSlave returns a pointer to a child interpreter of interp. The
child interpreter is identified by childName. If no such child inter-
preter exists, NULL is returned.
Tcl_GetChild is a synonym for Tcl_GetSlave. │
Tcl_GetMaster returns a pointer to the master interpreter of interp. If
interp has no master (it is a top-level interpreter) then NULL is re-
turned.
Tcl_GetParent is a synonym for Tcl_GetMaster. │
Tcl_GetInterpPath stores in the result of interp the relative path be-
tween 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 target-
Interp. The arguments specified by the strings contained in argv are
always prepended to any arguments supplied in the invocation of child-
Cmd and passed to targetCmd. This operation returns TCL_OK if it suc-
ceeds, 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 restric-
tions on the ancestry relationship (as created by Tcl_CreateSlave) be-
tween 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_GetAlias returns information 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 indi-
cated is set to the corresponding datum. For example, if targetNamePtr
is non-NULL it is set to a pointer to the string containing the name of
the target command.
Tcl_GetAliasObj is similar to Tcl_GetAlias except that it returns a
pointer to a vector of Tcl_Obj structures instead of a vector of
strings.
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 mes-
sage as the result of interp. If an exposed command named cmdName al-
ready exists, the operation returns TCL_ERROR and leaves an error mes-
sage 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 opera-
tion 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 com-
mand whose name is hiddenCmdName already exists, the operation also re-
turns 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).
SEE ALSO
interp
KEYWORDS
alias, command, exposed commands, hidden commands, interpreter, invoke,
parent, child
Tcl 7.6 Tcl_CreateAlias(3tcl)
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