Referring to the Command-Line Tail

MS-DOS                          | WINDOWS

The information in this article applies to:

• Microsoft C for MS-DOS, versions 5.0, 5.1, 6.0, 6.0a, and 6.0ax
• Microsoft C/C++ for MS-DOS, version 7.0
• Microsoft Visual C++ for Windows, versions 1.0 and 1.5

SUMMARY

The following code example demonstrates how an application can explicitly reference the command-line tail. The example accesses the Disk Transfer Area (DTA) to refer to the entire command line with spaces intact and prints the command line as one string.

In this method, the command line is limited to 128 bytes. If this code example is compiled as CMDLINE.EXE and invoked with the following command line

   cmdline *.c  abc  def  lab7.pas

   tail_length = 24
   cmd_tail = < *.c  abc  def  lab7.pas>

MORE INFORMATION

Sample Code

/*
 * Compile options needed: none
 */

#include <stdio.h>
#include <dos.h>

   int tail_length;
   char cmd_tail[128];
   char far *p;             /* far pointer */
   int i;

   struct SREGS Seg;
   union REGS Reg;

   Reg.h.ah = 0x2F;         /* DOS call:  Get DTA Address   */
   segread(&Seg);
   intdosx(&Reg, &Reg, &Seg);

   FP_SEG(p) = Seg.es;      /* make p point to the DTA */
   FP_OFF(p) = Reg.x.bx;

   tail_length = *p;        /* First byte is length of tail string */

   printf("tail_length = %d\n", tail_length);

   p++;                     /* Move to first byte */

   for(i = 0; i < tail_length; i++)
      cmd_tail[i] = p[i];

   cmd_tail[tail_length] = '\0';  /* Add NULL to make a string */
   printf("cmd_tail = <%s>\n", cmd_tail);

   return(0);