如何修改Erlang Makefile以启用SMP模式满足应用需求？

Hey there! Let's get your Erlang app running with SMP support by adjusting your Makefile. The issue is that your current Makefile isn't passing the -smp flag to the erl command when starting the app—here are the most common ways to fix this:

1. Update the ERL_FLAGS variable (recommended) #

Most Erlang Makefiles use the ERL_FLAGS variable to pass additional arguments to the erl executable. If your Makefile already defines this variable, simply add -smp to it:

# If ERL_FLAGS exists, append -smp
ERL_FLAGS += -smp

# Or if you're defining it from scratch:
ERL_FLAGS = -smp -name myapp@localhost -config config/sys.config

This ensures the -smp flag is included every time you run targets that use erl (like start, run, etc.).

2. Modify the direct erl command in your start target #

If your Makefile has a specific target (e.g., start) that calls erl directly, add the -smp flag to that command line:

start:
    erl -smp -name myapp@localhost -config config/sys.config -pa ebin/

Just insert -smp right after the erl command—this will force the SMP emulator to start when you run make start.

3. Verify it's working #

After making the change, start your app with make [your-start-target], then in the Erlang shell, run this command to confirm SMP is enabled:

erlang:system_info(smp_support).

If it returns true, you're all set! You can also check the process arguments (via tools like ps on Unix or Task Manager on Windows) to confirm the erl process is running with -smp.

内容的提问来源于stack exchange，提问作者Alvine Belle