This appendix explains how to write your own procedure to write or filter report output to a text driver. This function must be installed as a prototyped function; for more information on installation, refer to "Installing Prototyped Functions" in Application Development Guide.
To use an installed output function, specify it in the device file's
procedure statement. Use the
obuffsize statement to specify a buffer size greater than the default of 256 bytes. Refer to Appendix C, "Report Device Configuration Files," for more information on device configuration files.
The output function is declared with two parameters in this order: an integer-type code, and an output buffer.
Panther calls the function once with
RW_P_OPEN, once per line of output with
RW_P_WRITE, and once with
RW_P_WRITE, the buffer contains a line of output, terminated by the NEWLINE and NULL characters. Your procedure can modify the contents of the buffer.
Custom output procedures should return one of the codes listed in the following table.
Panther should output the buffer; the developer-written procedure has only filtered or analyzed the data.
Panther should not output the buffer; the developer-written procedure has handled this step.
Request for Panther to abort the rest of the report.
Invoking the Output Procedure
To use a custom report output procedure, specify the procedure's name in the
procedure parameter of the device configuration file. The default size for the output buffer is 256 bytes. You can specify a different size through the
obuffsize parameter of the device configuration file.