CODEWITHSUNDEEP
tcl
user3565150
user3565150

Reputation: 914

Global variable in Tcl

I am trying to use a global variable (gpio_out_set_3) by declaring it outside a function (because the variable might be used in other functions too in future). Inside the function, I have declared the same variable as 'global' and trying to access it through '$gpio_out_set_3'.

I am getting an error "can't read "gpio_out_set_3": no such variable"

set gpio_out_set_3 0x03
proc port2phy { device } {
   global gpio_out_set_3 
   erf_wr devcpu_gcb $gpio_out_set_3 $phy_mdc_gate_en
  }

Please help.

Upvotes: 3

Views: 18348

Answers (4)

Tomigo
Tomigo

Reputation: 1

Although newer versions of tcl allow for executable code to exist almost anywhere in your program, a good habit to form is to be sure that where you set the variable initially is in the main section of your program code. In order for your code to run properly on any version of tcl, there should be no executable code prior to, or in-between your procs (including set commands). All of your procs should go at the beginning of the program followed by your main code. Things that can/should go before your procs are comment lines and any necessary "package require ..." commands.

Upvotes: 0

betontalpfa
betontalpfa

Reputation: 3742

Declare all of your global variable at the beginning of your main file using variable command.

variable gpio_out_set_3 0x03

TIP: I dont like the global command. I always forget to use, and hard to see which variable is global and which variable is local. I prefer the $::<varname>, which points to the global namespace.

proc port2phy { device } {
   erf_wr devcpu_gcb $::gpio_out_set_3 $phy_mdc_gate_en
}

Upvotes: 7

Baltazar
Baltazar

Reputation: 53

My guess is that when you're creating variable gpio_out_set_3 you're not at top level. You are in some other procedure. So the gpio_out_set_3 in not really global, but instead local in some proc.

Upvotes: 2

Juergen
Juergen

Reputation: 996

Your global variable is named gpio_out_set_0 (not the same as gpio_out_set_3).

Upvotes: 0

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