Function            isMCA - is the bus Micro Channel Architecture

  Syntax              int isMCA(void);

  Prototype in        ibm.h

  Remarks             isMCA() detects if the bus is Micro Channel
                      Architecture.

  Return value        returns 1 if the bus is Micro Channel Architecture,
                      0 if it is not, and -1 if this function is not
                      supported.

  Note                the 1/10/86 XT BIOS returns an incorrect value for
                      this function, so if the machine is an IBM XT or
                      compatible with a BIOS date of 1/10/86, do not use
                      this function.

  See also            machine_id(), ROM_date(), ROM_id()

  Example             #include <ibm.h>

                      main()
                      {
                           printf("BUS type: ");
                           switch (isMCA()) {
                                case -1: printf("Error");  break;
                                case  0: printf("PC");  break;
                                case  1: printf("MCA");  break;
                      }