argc is a global [namespace] [Tcl] variable set by [tclsh], [wish] and other code doing similar setup.

It contains a count of the number of arguments passed to the command upon invocation.

The count begins at 1, and the count does not include the name of the script itself (which in [tclsh] can be found in [argv0])
or the name of the Tcl interpreter (which is reported by [info nameofexecutable])
(both of which are different from C's `argc`).

======
# program usage requires at least one argument
if { $::argc eq 0 } {
   puts "USAGE: $::argv0 argument"
   exit 1
}
======

----
**See also**
   * [argv]
   * [argc]
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