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info(n) Tcl Built-In Commands info(n)
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NAME
info - Return information about the state of the Tcl interpreter
SYNOPSIS
info option ?arg arg ...?
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DESCRIPTION
This command provides information about various internals of the Tcl interpreter. The legal options
(which may be abbreviated) are:
info args procname
Returns a list containing the names of the arguments to procedure procname, in order. Proc-name Procname
name must be the name of a Tcl command procedure.
info body procname
Returns the body of procedure procname. Procname must be the name of a Tcl command procedure.
info cmdcount
Returns a count of the total number of commands that have been invoked in this interpreter.
info commands ?pattern?
If pattern is not specified, returns a list of names of all the Tcl commands visible (i.e. |
executable without using a qualified name) to the current namespace, including both the built- |
in commands written in C and the command procedures defined using the proc command. If pat- |
tern is specified, only those names matching pattern are returned. Matching is determined |
using the same rules as for string match. pattern can be a qualified name like Foo::print*. |
That is, it may specify a particular namespace using a sequence of namespace names separated |
by double colons (::), and may have pattern matching special characters at the end to specify |
a set of commands in that namespace. If pattern is a qualified name, the resulting list of |
command names has each one qualified with the name of the specified namespace, and only the |
commands defined in the named namespace are returned.
info complete command
Returns 1 if command is a complete Tcl command in the sense of having no unclosed quotes,
braces, brackets or array element names. If the command does not appear to be complete then 0
is returned. This command is typically used in line-oriented input environments to allow
users to type in commands that span multiple lines; if the command is not complete, the
script can delay evaluating it until additional lines have been typed to complete the command.
info default procname arg varname
Procname must be the name of a Tcl command procedure and arg must be the name of an argument
to that procedure. If arg does not have a default value then the command returns 0. Other-wise Otherwise
wise it returns 1 and places the default value of arg into variable varname.
info exists varName
Returns 1 if the variable named varName exists in the current context (either as a global or
local variable) and has been defined by being given a value, returns 0 otherwise.
info frame ?number?
This command provides access to all frames on the stack, even those hidden from info level. If
number is not specified, this command returns a number giving the frame level of the command.
This is 1 if the command is invoked at top-level. If number is specified, then the result is a
dictionary containing the location information for the command at the numbered level on the
stack.
If number is positive (> 0) then it selects a particular stack level (1 refers to the top-most
active command, i.e., info frame itself, 2 to the command it was called from, and so on); oth-erwise otherwise
erwise it gives a level relative to the current command (0 refers to the current command,
i.e., info frame itself, -1 to its caller, and so on).
This is similar to how info level works, except that this subcommand reports all frames, like
sourced scripts, evals, uplevels, etc.
Note that for nested commands, like "foo [bar [x]]", only "x" will be seen by an info frame
invoked within "x". This is the same as for info level and error stack traces.
The result dictionary may contain the keys listed below, with the specified meanings for their
values:
type This entry is always present and describes the nature of the location for the command.
The recognized values are source, proc, eval, and precompiled.
source
means that the command is found in a script loaded by the source command.
proc
means that the command is found in dynamically created procedure body.
eval
means that the command is executed by eval or uplevel.
precompiled
means that the command is found in a precompiled script (loadable by the package
tbcload), and no further information will be available.
line This entry provides the number of the line the command is at inside of the script it is
a part of. This information is not present for type precompiled. For type source this
information is counted relative to the beginning of the file, whereas for the last two
types the line is counted relative to the start of the script.
file This entry is present only for type source. It provides the normalized path of the file
the command is in.
cmd This entry provides the string representation of the command. This is usually the
unsubstituted form, however for commands which are a pure list executed by eval it is
the substituted form as they have no other string representation. Care is taken that
the pure-List property of the latter is not spoiled.
proc This entry is present only if the command is found in the body of a regular Tcl proce-dure. procedure.
dure. It then provides the name of that procedure.
lambda This entry is present only if the command is found in the body of an anonymous Tcl pro-cedure, procedure,
cedure, i.e. a lambda. It then provides the entire definition of the lambda in ques-tion. question.
tion.
level This entry is present only if the queried frame has a corresponding frame returned by
info level. It provides the index of this frame, relative to the current level (0 and
negative numbers).
A thing of note is that for procedures statically defined in files the locations of commands
in their bodies will be reported with type source and absolute line numbers, and not as type
proc. The same is true for procedures nested in statically defined procedures, and literal
eval scripts in files or statically defined procedures.
In contrast, a procedure definition or eval within a dynamically evaluated environment count
linenumbers relative to the start of their script, even if they would be able to count rela-tive relative
tive to the start of the outer dynamic script. That type of number usually makes more sense.
A different way of describing this behaviour is that file based locations are tracked as
deeply as possible, and where this is not possible the lines are counted based on the smallest
possible eval or procedure body, as that scope is usually easier to find than any dynamic
outer scope.
The syntactic form {*} is handled like eval. I.e. if it is given a literal list argument the
system tracks the linenumber within the list words as well, and otherwise all linenumbers are
counted relative to the start of each word (smallest scope)
info functions ?pattern?
If pattern is not specified, returns a list of all the math functions currently defined. If
pattern is specified, only those functions whose name matches pattern are returned. Matching
is determined using the same rules as for string match.
info globals ?pattern?
If pattern is not specified, returns a list of all the names of currently-defined global vari-ables. variables.
ables. Global variables are variables in the global namespace. If pattern is specified, only
those names matching pattern are returned. Matching is determined using the same rules as for
string match.
info hostname
Returns the name of the computer on which this invocation is being executed. Note that this
name is not guaranteed to be the fully qualified domain name of the host. Where machines have
several different names (as is common on systems with both TCP/IP (DNS) and NetBIOS-based net-working networking
working installed,) it is the name that is suitable for TCP/IP networking that is returned.
info level ?number?
If number is not specified, this command returns a number giving the stack level of the invok-ing invoking
ing procedure, or 0 if the command is invoked at top-level. If number is specified, then the
result is a list consisting of the name and arguments for the procedure call at level number
on the stack. If number is positive then it selects a particular stack level (1 refers to the
top-most active procedure, 2 to the procedure it called, and so on); otherwise it gives a
level relative to the current level (0 refers to the current procedure, -1 to its caller, and
so on). See the uplevel command for more information on what stack levels mean.
info library
Returns the name of the library directory in which standard Tcl scripts are stored. This is
actually the value of the tcl_library variable and may be changed by setting tcl_library. See
the tclvars manual entry for more information.
info loaded ?interp?
Returns a list describing all of the packages that have been loaded into interp with the load
command. Each list element is a sub-list with two elements consisting of the name of the file
from which the package was loaded and the name of the package. For statically-loaded packages
the file name will be an empty string. If interp is omitted then information is returned for
all packages loaded in any interpreter in the process. To get a list of just the packages in
the current interpreter, specify an empty string for the interp argument.
info locals ?pattern?
If pattern is not specified, returns a list of all the names of currently-defined local vari-ables, variables,
ables, including arguments to the current procedure, if any. Variables defined with the
global, upvar and variable commands will not be returned. If pattern is specified, only
those names matching pattern are returned. Matching is determined using the same rules as for
string match.
info nameofexecutable
Returns the full path name of the binary file from which the application was invoked. If Tcl
was unable to identify the file, then an empty string is returned.
info patchlevel
Returns the value of the global variable tcl_patchLevel; see the tclvars manual entry for more
information.
info procs ?pattern?
If pattern is not specified, returns a list of all the names of Tcl command procedures in the
current namespace. If pattern is specified, only those procedure names in the current names-pace namespace
pace matching pattern are returned. Matching is determined using the same rules as for string
match. If pattern contains any namespace separators, they are used to select a namespace rel-ative relative
ative to the current namespace (or relative to the global namespace if pattern starts with ::)
to match within; the matching pattern is taken to be the part after the last namespace separa-tor. separator.
tor.
info script ?filename?
If a Tcl script file is currently being evaluated (i.e. there is a call to Tcl_EvalFile active
or there is an active invocation of the source command), then this command returns the name of
the innermost file being processed. If filename is specified, then the return value of this
command will be modified for the duration of the active invocation to return that name. This
is useful in virtual file system applications. Otherwise the command returns an empty string.
info sharedlibextension
Returns the extension used on this platform for the names of files containing shared libraries
(for example, .so under Solaris). If shared libraries are not supported on this platform then
an empty string is returned.
info tclversion
Returns the value of the global variable tcl_version; see the tclvars manual entry for more
information.
info vars ?pattern?
If pattern is not specified, returns a list of all the names of currently-visible variables.
This includes locals and currently-visible globals. If pattern is specified, only those names
matching pattern are returned. Matching is determined using the same rules as for string
match. pattern can be a qualified name like Foo::option*. That is, it may specify a particu-lar particular
lar namespace using a sequence of namespace names separated by double colons (::), and may
have pattern matching special characters at the end to specify a set of variables in that
namespace. If pattern is a qualified name, the resulting list of variable names has each
matching namespace variable qualified with the name of its namespace. Note that a currently-visible currentlyvisible
visible variable may not yet "exist" if it has not been set (e.g. a variable declared but not
set by variable).
EXAMPLE
This command prints out a procedure suitable for saving in a Tcl script:
proc printProc {procName} {
set result [list proc $procName]
set formals {}
foreach var [info args $procName] {
if {[info default $procName $var def]} {
lappend formals [list $var $def]
} else {
# Still need the list-quoting because variable
# names may properly contain spaces.
lappend formals [list $var]
}
}
puts [lappend result $formals [info body $procName]]
}
SEE ALSO
global(n), proc(n)
KEYWORDS
command, information, interpreter, level, namespace, procedure, variable
Tcl 8.4 info(n)
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