Hint Directives

Using Hint Directives

Whenever an identifier marked with a hint directive is later encountered by the compiler, then a warning will be displayed, corresponding to the specified hint.

• deprecated
  • The use of this identifier is deprecated, use an alternative instead. The deprecated keyword can be followed by a string constant with a message. The compiler will show this message whenever the identifier is encountered.
• experimental
  • The use of this identifier is experimental: this can be used to flag new features that should be used with caution.
• platform
  • This is a platform-dependent identifier: it may not be defined on all platforms.
• unimplemented
  • This should be used on functions and procedures only. It should be used to signal that a particular feature has not yet been implemented.

The following are examples:

Const
  AConst = 12 deprecated;

var
  p : integer platform;

Function Something : Integer; experimental;

begin
  Something:=P+AConst;
end;

begin
  Something;
end.

This would result in the following output:

testhd.pp(11,15) Warning: Symbol "p" is not portable
testhd.pp(11,22) Warning: Symbol "AConst" is deprecated
testhd.pp(15,3) Warning: Symbol "Something" is experimental

Hint directives can follow all kinds of identifiers: units, constants, types, variables, functions, procedures and methods.

From the Free Pascal wiki, page "Hint Directives", as it stood on 2020-06-23 after a change by Kai Burghardt, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's Licensing page. If you have concerns about this material, message the admin.