incr(n) Tcl Built-In Commands incr(n)
NAME
incr - Increment the value of a variable
SYNOPSIS
incr varName ?increment?
DESCRIPTION
Increments the value stored in the variable whose name is varName. The
value of the variable must be an integer. If increment is supplied
then its value (which must be an integer) is added to the value of
variable varName; otherwise 1 is added to varName. The new value is
stored as a decimal string in variable varName and also returned as
result.
Starting with the Tcl 8.5 release, the variable varName passed to incr
may be unset, and in that case, it will be set to the value increment
or to the default increment value of 1.
EXAMPLES
Add one to the contents of the variable x:
incr x
Add 42 to the contents of the variable x:
incr x 42
Add the contents of the variable y to the contents of the variable x:
incr x $y
Add nothing at all to the variable x (often useful for checking whether
an argument to a procedure is actually integral and generating an error
if it is not):
incr x 0
SEE ALSO
expr(n), set(n)
KEYWORDS
add, increment, variable, value
Tcl incr(n)
tcl 8.6.0 - Generated Wed Jan 9 15:20:14 CST 2013