Question

When debuging gen_server module, I want to record more details status.

init()->
    put(?COMPLETED_COMMANDS,[]),
-ifdef(DEBUG).
    put(?DETAIL_STATUS,[]),
-endif.
    ok.

The compiler give the following error.

src/benvolio_command_cache.erl:34: syntax error before: ','
src/benvolio_command_cache.erl:36: syntax error before: '.'
src/benvolio_command_cache.erl:33: variable 'DEBUG' is unbound
src/benvolio_command_cache.erl:33: function ifdef/1 undefined

How to add debuging code lines in the *.erl file’s function?

Answer 1

Macro directives cannot be used inside functions. see 8.5 Flow Control in Macros.