mrd_lock - Send a SCSI Prevent-Allow Media Removal command

    Windows NT         mrd.dll
    UNIX               /usr/lib/libmrd.a
    OpenVMS            MRD$RTL.EXE

    #include <mrd_common.h>
    #include <mrd_message.h>

    int mrd_lock(
        const char *robot_name,
        const int   lock_value,
        char       *log_info) ;