HP 3000 Manuals

HP Business BASIC/XL Reference Manual

Example of a Simple C ANYPARM Procedure 

This section contains a C procedure that can be called from HP Business
BASIC/XL using the ANYPARM call interface.  This procedure shows how to
define the actual parameter table that the ANYPARM call requires.  It
also contains an example procedure that accepts the actual parameter
table as a formal parameter.

     #define C_MAX_NUM_PARAMETERS  50
     #define C_SINTEGER_TYPE        5  /* identifies BASIC SHORT INTEGER type */
     #define C_INTEGER_TYPE        11  /* identifies BASIC INTEGER type       */
     union u_scalar_value{             /* union to access parameter appropriately */
        short sinteger_value;
        int   integer_value;
     } scalar_value;

     struct parameter_record{          /* entry in the actual parameter array     */
        union u_scalar_value *param_address;
        short param_type;
        short number_of_dimensions;
     };

     /* simple_example
        simple_example is a procedure written to be called by the BASIC ANYPARM
        call mechanism.  A loop prints the values of scalar 16 and 32 bit integers
        and prints error messages for all other entries in the actual parameter
        table.
     */
     simple_example(num_params, p_actual_param_table)
     int num_params;
     struct parameter_record p_actual_param_table[];
     {
        int param_index;
        printf("Number of parameters passed to SIMPLE EXAMPLE is:%3d\n",
                num_params);
        if (num_params > C_MAX_NUM_PARAMETERS) {
           printf("Too many actual parameters passed to SIMPLE EXAMPLE.\n");
           printf("Maximum number is: %d\n", C_MAX_NUM_PARAMETERS);
           exit(0);
        }
        for (param_index = 0; param_index < num_params; param_index++){
           printf("%3d   ", (param_index+1));
           if (p_actual_param_table[param_index].number_of_dimensions == 0){
              switch (p_actual_param_table[param_index].param_type){
                 case C_SINTEGER_TYPE:
                    printf("SHORT INTEGER %d\n", (*p_actual_param_table[param_index].
                       param_address).sinteger_value);
                    break;
                 case C_INTEGER_TYPE:
                    printf("INTEGER       %d\n", (*p_actual_param_table[param_index].
                       param_address).integer_value
                      );
                    break;
                 default:
                    printf("Actual parameter to SIMPLE EXAMPLE has an invalid");
                    printf(" data type.\n");
              }
           } else {
              printf("Actual parameter to SIMPLE EXAMPLE must be a scalar.\n");
           }
        }
     }

Calling the C External SIMPLE_EXAMPLE 

Assume that the C program presented in the previous section is in the
file, CPROG. To add the SIMPLE_EXAMPLE procedure to the local executable
library named XL, do the following:

     :ccxl cprog
     :linkeditor
     linked>buildxl xl
     linked>addxl from=$oldpass; to=xl
     linked>exit
     :

The output from the C procedure is the same as that from the Pascal
procedure in the previous section.

MPE/iX 5.0 Documentation