This function determines the set of modules to compile and the compile options to use, by first looking for the emake make option, if not present reads the configuration from a file named Emakefile (see below). If no such file is found, the set of modules to compile defaults to all modules in the current working directory.

Traversing the set of modules, it then recompiles every module for which at least one of the following conditions apply:

• there is no object file, or
• the source file has been modified since it was last compiled, or,
• an include file has been modified since the source file was last compiled.

As a side effect, the function prints the name of each module it tries to compile. If compilation fails for a module, the make procedure stops and error is returned.

Options is a list of make- and compiler options. The following make options exist:

• noexec
  No execution mode. Just prints the name of each module that needs to be compiled.
• load
  Load mode. Loads all recompiled modules.
• netload
  Net load mode. Loads all recompiled modules on all known nodes.
• {emake, Emake}
  Rather than reading the Emakefile specify configuration explicitly.

All items in Options that are not make options are assumed to be compiler options and are passed as-is to compile:file/2. Options defaults to [].

files/1,2 does exactly the same thing as all/0,1 but for the specified ModFiles, which is a list of module or file names. The file extension .erl may be omitted.

The Emakefile (if it exists) in the current directory is searched for compiler options for each module. If a given module does not exist in Emakefile or if Emakefile does not exist, the module is still compiled.