'''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.

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See also:

   * [info]

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Called with a variable or array element name (no $ in front!), returns 1 if the variable or array element exists, else 0.

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[Category Command] - [Tcl syntax help]