user interface - tk_optionMenu error "can't read "a": no such variable" -
i trying execute simple code
global eval tk_optionmenu .qt.oc [list 1 2 4 8 16] proc run {} { puts "$a" }
i have button associated run proc , when press pres on run button receive following error:
can't read "a": no such variable can't read "a": no such variable while executing "puts "$a"" (procedure "run" line 2) invoked within "run" invoked within ".top.run invoke" ("uplevel" body line 1) invoked within "uplevel #0 [list $w invoke]" (procedure "tk::buttonup" line 22) invoked within "tk::buttonup .top.run" (command bound event)
any suggestions?
global
must used inside scope trying access global variable. example:
proc run {} { global puts "$a" }
here's excerpt global man page:
this command has no effect unless executed in context of proc body.
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