os/proc-close

    cfunction
    src/core/os.c on line 813, column 1

    (os/proc-close proc)

    Close pipes created for subprocess `proc` by `os/spawn` if they 
    have not been closed. Then, if `proc` is not being waited for, 
    wait. If this function waits, when `proc` completes, return the 
    exit code of `proc`. Otherwise, return nil.