[R] Which external functions are called in a package?

[Hans W Borchers]

How can I find out which functions of my package A are called within
another package B that depends on, imports, or suggests package A ?
And more specifically, which functions in B are calling functions in A ?

I tried to utilize the *pkgapi* package, but get error messages like

    > map_package("./R/x86_64-pc-linux-gnu-library/3.6/cranlogs")

    Error: <callr_status_error: callr subprocess failed:
        invalid first argument>
    -->
    <callr_remote_error in mget(targets, envir = env,
        mode = "function", inherits = TRUE,  ...:
     invalid first argument>
     in process 22909

(1) What do these error messages mean?

(2) Are there easier ways to get this information?

Thanks in advance. --HW