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How to read random variable name?

4 posts

bostko#

How to read random variable name?

I want to save target installation directory in ini file.
So the installation directory could be $LOCALAPPDATA or $APPDATA etc.
But how could I store variable name I want to use and then use it.
It needs to be some way like that


I hope you will understand my question 🙂
Afrow UK#
I would store a string/int and then on read do:
ReadINIStr $R0 ...

${If} $R0 == $$LOCALAPPDATA

  StrCpy $INSTDIR $LOCALAPPDATA

${ElseIf} $R0 == $$APPDATA

  StrCpy $INSTDIR $APPDATA

...
If you need to store a sub folder path/name then I'd use another INI key/value pair for it. The other option is to evaluate $$APPDATA (etc) from a read value using StrReplace (or WordFunc equiv) but IMO that is a bit messy/ugly.

Edit: But why would you want to store the variable names? Why not just store the value of $INSTDIR. Otherwise, if on uninstall, say $APPDATA has changed then your evaluated $INSTDIR will not be valid.

Stu
Animaether#
Usually you would store the full path in the ini file or the environment variable ( http://www.wilsonmar.com/1envvars.htm - see also: REG_EXPAND_SZ ) for the applicable part of the path. Storing NSIS variable names work as well, I suppose, but you can't read them out directly.

You'd have to use something like...
/* write the -name- $LOCALAPPDATA to ini */
WriteIniStr "filename.ini" "Section" "Location" "$$LOCALAPPDATA"
/* read the -name- of variable to ini */
ReadIniStr $0 "filename.ini" "Section" "Location"
/* Select the actual value of the variable depending on the name */
${Select} "$0"
${Case} "$$LOCALAPPDATA"
    StrCpy $0 "$LOCALAPPDATA"
${EndSelect}