.ERR1            Force Error during Pass 1                     MASM Directive

  .ERR1

    Forces a warning error during Pass 1 of the assembly provided the /D
    command line switch has been used to generate a Pass 1 listing.

       Notes:     This directive could be used within conditional-assembly
                  blocks or macros to see what is expanded.

                  The error message that is generated by this directive is
                  'Forced error - pass1', which is error number 87.

                  This directive has no effect if the /D command line
                  switch is not used.

                  This conditional error directive will only generate a
                  warning error, not a fatal error.