GLOBAL VARIABLE :HOW USE IT?

hi, i want to use it in a function..example:

function CaricaManageInstrument()
global dd
dd=5;
end

>> CaricaManageInstrument()

>> dd

Unrecognized function or variable 'dd'.

Answer 1

[Star Strider]

Please do not ever use global variables.

Use the approach described in Passing Extra Parameters instead.

Answer 2

[Walter Roberson]

Global variables are only reachable within the current workspace. Consider the following code:

first(); second(); third();

a = 'set by first'

function first
  global a
  a = 'set by first';
end
function second
   a = 'set by second';
end
function third
   global a
   a
end

The result is not 'set by second' because for global variables, the connection between the name and the global variable is only made in workspaces that "opt in" to the connection by explicitly declaring the variable global.

Your function CaricaManageInstrument opts in to connecting "dd" to the global variable, but once you have returned to the base workspace (the command line), the base workspace has not opted into the connection between the name and the global variable.

Answer 3

[Image Analyst]

See the FAQ:

https://matlab.fandom.com/wiki/FAQ#Are_global_variables_bad?