[ros-dev] Const Error

[Mike Nordell]

James Tabor wrote:

> const PCHAR const HelloString = "Hello\n";
>                ^
>                | is that right?

No.

Assuming PCHAR is just a (IMO basically useless) "typedef char* PCHAR;",
then "const PCHAR" would mean nothing, since you can't modify the
cv-qualification of a typedef like this (cv is C and C++ standard lingo,
meaning "const/volatile"). This is one of the reasons such stupid typedefs
are bad - the only way to make them point to a const object is by adding yet
_another_ typedef: "typedef const char* PCCHAR;" (or CPCHAR if you're into
that kind of naming :-) ), or by literally using the real type the typedef
refers to.

I suspect the well-meaning intention, but not equally informed wrt
cv-qualification and typedefs, was:

  const char* HelloString const = ...

but why anyone would do something like that instead of just

  const char HelloString[] = ...

or if wanting to make the code more obscure, harder to understand and
therefore less maintainable

  LPCSTR const HelloString = ...

I don't understand.

--
/Mike