Tcl_CreateSlave(3) Tcl Library Procedures Tcl_CreateSlave(3)______________________________________________________________________________NAME
Tcl_IsSafe, Tcl_MakeSafe, Tcl_CreateSlave, Tcl_GetSlave, Tcl_GetMaster,
Tcl_GetInterpPath, 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_CreateSlave(interp, slaveName, isSafe)
Tcl_Interp *
Tcl_GetSlave(interp, slaveName)
Tcl_Interp *
Tcl_GetMaster(interp)
int
Tcl_GetInterpPath(askingInterp, slaveInterp)
int │
Tcl_CreateAlias(slaveInterp, slaveCmd, targetInterp, targetCmd, argc, argv)│
int │
Tcl_CreateAliasObj(slaveInterp, slaveCmd, targetInterp, targetCmd, objc, objv)│
int
Tcl_GetAlias(interp, slaveCmd, targetInterpPtr, targetCmdPtr, argcPtr, argvPtr)
int │
Tcl_GetAliasObj(interp, slaveCmd, 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 spec‐ │
ified command. │
CONST char *slaveName (in) │
Name of slave inter‐ │
preter to create or │
manipulate. │
int isSafe (in) │
If non-zero, a │
``safe'' slave that │
is suitable for run‐ │
ning untrusted code │
is created, other‐ │
wise a trusted slave │
is created. │
Tcl_Interp *slaveInterp (in) │
Interpreter to use │
for creating the │
source command for │
an alias (see │
below). │
CONST char *slaveCmd (in) │
Name of source com‐ │
mand for alias. │
Tcl_Interp *targetInterp (in) │
Interpreter that │
contains the target │
command 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 │
object arguments to │
pass to the alias │
object command. │
Tcl_Object **objv (in) │
Vector of Tcl_Obj │
structures, the │
additional object │
arguments to pass to │
the alias object │
command. This stor‐ │
age 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 │
additional 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 │
storage owned by the │
caller, the vector │
of strings is owned │
by the called func‐ │
tion. │
int *objcPtr (out) │
Pointer to location │
to store count of │
additional object │
arguments to be │
passed to the alias. │
The location 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 │
object alias com‐ │
mand. The location │
is in storage owned │
by the caller, the │
vector of Tcl_Obj │
structures is owned │
by the called func‐ │
tion. │
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 inter‐
preters 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
result field of the interpreter contains an error message.
Tcl_CreateSlave creates a new interpreter as a slave of interp. It
also creates a slave command named slaveName in interp which allows
interp to manipulate the new slave. If isSafe is zero, the command
creates a trusted slave in which Tcl code has access to all the Tcl
commands. If it is 1, the command creates a ``safe'' slave 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 slave 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_MakeSafe marks interp as ``safe'', so that future calls to
Tcl_IsSafe will return 1. It also removes all known potentially-unsafe
core functionality (both commands and variables) from interp. However,
it cannot know what parts of an extension or application are safe and
does not make any attempt to remove those parts, so safety is not guar‐
anteed after calling Tcl_MakeSafe. Callers will want to take care with
their use of Tcl_MakeSafe to avoid false claims of safety. For many
situations, Tcl_CreateSlave may be a better choice, since it creates
interpreters in a known-safe state.
Tcl_GetSlave returns a pointer to a slave interpreter of interp. The
slave interpreter is identified by slaveName. If no such slave inter‐
preter exists, NULL is returned.
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
returned.
Tcl_GetInterpPath sets the result field in askingInterp to the relative
path between askingInterp and slaveInterp; slaveInterp must be a slave
of askingInterp. If the computation of the relative path succeeds,
TCL_OK is returned, else TCL_ERROR is returned and the result field in
askingInterp contains the error message.
Tcl_CreateAlias creates an object command named slaveCmd in slaveInterp │
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 │
slaveCmd 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 object result of slaveInterp. Note that there are no │
restrictions on the ancestry relationship (as created by Tcl_Cre‐ │
ateSlave) between slaveInterp 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 objects 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 in the result field in interp. If an exposed command named cmd‐ │
Name already exists, the operation returns TCL_ERROR and leaves an │
error message in the object result of interp. If the operation suc‐ │
ceeds, it returns TCL_OK. After executing this command, attempts to │
use cmdName in a call to Tcl_Eval or with the Tcl eval command 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 in the object │
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 in the object result of interp. The CmdName │
will be looked up in the global namespace, and not relative to the cur‐ │
rent 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 the result field in interp con‐ │
tains an error message. If the operation succeeds, it returns TCL_OK. │
After executing this command, attempts to use cmdName in a call to │
Tcl_Eval or with the Tcl eval command will fail. │
For a description of the Tcl interface to multiple interpreters, see │
interp(n). │
SEE ALSO │
interp │
KEYWORDS │
alias, command, exposed commands, hidden commands, interpreter, invoke, │
master, slave │
Tcl 7.6 Tcl_CreateSlave(3)
