QBUF


>>-QBUF--------------------------------------------------------><

queries the number of buffers that were created on the data stack with the MAKEBUF command. The QBUF command returns the number of buffers in the REXX special variable RC. If you have not issued MAKEBUF to create any buffers on the data stack, QBUF sets the special variable RC to 0. In this case, 0 is the number of the buffer that is contained in every data stack.

You can use the QBUF command in REXX execs that run in both the TSO/E address space and non-TSO/E address spaces.

QBUF returns the current number of data stack buffers created by an exec and by other routines (functions and subroutines) the exec calls. You can issue QBUF from the calling exec or from a called routine. For example, if an exec issues two MAKEBUF commands and then calls a routine that issues another MAKEBUF command, QBUF returns 3 in the REXX special variable RC.

The following table shows how QBUF sets the REXX special variable RC.

Return code	Meaning
0	Only buffer 0 exists on the data stack
1	One additional buffer exists on the data stack
2	Two additional buffers exist on the data stack
n	n additional buffers exist on the data stack

Examples

If an exec creates two buffers on the data stack using the MAKEBUF command, deletes one buffer using the DROPBUF command, and then issues the QBUF command, RC is set to 1.

"MAKEBUF"            /* buffer created */
⋮
"MAKEBUF"            /* second buffer created */
⋮
"DROPBUF"            /* second buffer created is deleted */
"QBUF"
SAY 'The number of buffers created is' RC      /* RC = 1 */

Suppose an exec uses MAKEBUF to create a buffer and then calls a routine that also issues MAKEBUF. The called routine then calls another routine that issues two MAKEBUF commands to create two buffers. If either of the called routines or the original exec issues the QBUF command, QBUF sets the REXX special variable RC to 4.

"DROPBUF 0"     /* delete any buffers MAKEBUF created */
"MAKEBUF"                     /* create one buffer    */
SAY 'Buffers created = ' RC               /*  RC = 1  */
CALL sub1
"QBUF"
SAY 'Buffers created = ' RC               /*  RC = 4  */
EXIT

sub1:
"MAKEBUF"                     /* create second buffer */
SAY 'Buffers created = ' RC               /*  RC = 2  */
CALL sub2
"QBUF"
SAY 'Buffers created = ' RC               /*  RC = 4  */
RETURN

sub2:
"MAKEBUF"                     /* create third buffer  */
SAY 'Buffers created = ' RC               /*  RC = 3  */
⋮
"MAKEBUF"                     /* create fourth buffer */
SAY 'Buffers created = ' RC               /*  RC = 4  */
RETURN