Helpful commands for the erl shell

Show all processes

pman:start()

Show all applications

appmon:start()

Useful code snippets

Managing erlang build process

Erlang builds using Makefile

• Pittfalls:
  • Always use tabs in Makefile
    Otherwise following error may occur: Makefile:8: *** missing separator. Schluss.
• Example: all: erlc -pa . -o ebin/ src/*.erl test/*.erl test: all erl -pa ebin/ -eval 'eunit:test(testfile), init:stop().' dialyze: dialyzer src/*.erl test/*.erl full: all test dialyze

Code Pitfalls

Correct PID assignment

The code fragment spawn(fun() -> something(self()) end) does not pass the current PID in to the fun function, but instead creates a new PID that is used. To achieve the correct behaviour, the PID has to be assigned first: P = self(), spawn(fun() -> something(P) end)

Analyzing erlang programs

The Dialyzer, a DIscrepancy AnalYZer for ERlang programs

• Pittfalls:
  • In order to use dializer the first time, it has to be initialized by executing "dialyzer --build_plt --apps erts kernel stdlib"
    otherwise the following message may occur: "Could not find the PLT" and/or "Byte code compiled with debug_info is needed to build the PLT"

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