This function is used to turn formatting off or on. It corresponds to the :lines. tag.

#define INCL_DDF
#include <os2.h>

HDDF     hddf;         /*  Handle to DDF returned by DdfInitialize. */
ULONG    fFormatType;  /*  Formatting-activation flag. */
BOOL     rc;           /*  Success indicator. */

rc = DdfSetFormat(hddf, fFormatType);