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Add 'changed' status to varGetValue #1

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Add 'changed' status to varGetValue #1

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@sclaiborne sclaiborne commented Dec 3, 2021 •
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Important notes:

  1. (w)Strings with lengths longer than VAR_STRLEN_NAME (120) chars will only report on change if its in the first 120 chars
  2. This increases the stack size of call by VAR_STRLEN_NAME (120) + UDINT (4) bytes
  3. This increases cpu usage of the call by about 1 strlen (max 120 chars) and 1 strcmp (max 120 chars)

@sclaiborne sclaiborne changed the title Add 'change' status to varGetValue Add 'changed' status to varGetValue Dec 3, 2021
sclaiborne
sclaiborne commented Dec 3, 2021
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varGetValue.c

// Check for value changed
if( valueStringLen != strlen(ipVariable->value)
|| strcmp( valueString, ipVariable->value )) {
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@sclaiborne sclaiborne Dec 3, 2021

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Should this instead be memcmp as we know the string lengths are already the same? I am not sure if that optimization gains us much if anything.

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