The usage of macro

If I define a macro, for example, !define MY_WALLET "empty". When I use MY_WALLET this way, MessageBox MB_OK $MY_WALLET, then "$MY_WALLET" will be displayed. In order to display "empty", I have to use it like MessageBox MB_OK ${MY_WALLET}. Why? Thanks.

You define macros with !macro, not !define. Why would you use $MY_WALLET? It's not a variable. The ${} is there for that distinction.

Stu

Originally Posted by Afrow UK View Post

You define macros with !macro, not !define. Why would you use $MY_WALLET? It's not a variable. The ${} is there for that distinction.

Stu

But we use $1 or $R0 as variables. So I guess ${} is for user defined variable and $ is system defined variable like $1 or $R0. Am I right? Thanks.

No! You really need to read the manual. !define creates a constant not a variable. Var creates a user variable. User variables and NSIS registers ($R0-$R9, $0-$9) use the same syntax ($var). Constants use ${constant}. Constants are evaluated at compile time, i.e. their place-holder (${constant}) is substituted with their value at compile time. The actual constant no longer exists in the built installer executable. This goes for every command that begins with a !, hence why they are in the manual under compile time commands. Not sure why I am answering this - you really should look this stuff up.

Edit: And don't confuse run-time constants (e.g. $SYSDIR) with compile-time constants (${myconstant}). They are not the same. $SYSDIR (etc.) is like a special variable which has its value set before .onInit, but you cannot write to it.

Stu

Originally Posted by Afrow UK View Post

No! You really need to read the manual. !define creates a constant not a variable. Var creates a user variable. User variables and NSIS registers ($R0-$R9, $0-$9) use the same syntax ($var). Constants use ${constant}. Constants are evaluated at compile time, i.e. their place-holder (${constant}) is substituted with their value at compile time. The actual constant no longer exists in the built installer executable. This goes for every command that begins with a !, hence why they are in the manual under compile time commands. Not sure why I am answering this - you really should look this stuff up.

Edit: And don't confuse run-time constants (e.g. $SYSDIR) with compile-time constants (${myconstant}). They are not the same. $SYSDIR (etc.) is like a special variable which has its value set before .onInit, but you cannot write to it.

Stu

Thanks for your explainations! I will also check the manual.