HP 3000 Manuals HP 3000 Manuals
INTERACTIVE USE OF SETDUMP If you enter the :SETDUMP command before running your program or if the SETDUMP intrinsic is included in a program run interactively, control transfers to DEBUG if the program terminates abnormally. A stack trace analysis is displayed and then the program enters DEBUG mode so that you can enter any of the DEBUG commands described in Section III. Any SETDUMP parameters are ignored.
NOTE If a program aborts in the system SL only the stack marker trace will be given. You will not enter DEBUG (in the interactive case) nor will there be a STACKDUMP in JOBS. This is done for security reasons.
USING :SETDUMP COMMAND INTERACTIVELY To illustrate the use of :SETDUMP in interactive mode, suppose you are running program DBPROG2 for the first time. You can precede the :RUN command by a :SETDUMP command and, if the program aborts, you can then use DEBUG to determine the cause and possibly correct it. In the example in Figure 4-1, DBPROG2 terminates with an integer overflow. The status of the aborted program in the example shows that the user traps are set (bit 2=1). As a result, the overflow bit (bit 4) is not set even though an overflow occurred. This is a result of the way the interrupt system operates. Following the stack analysis, the DEBUG prompt is issued. In response, you can perform any of the standard DEBUG operations. For instance, if you simply want to bypass the erroneous statement, you can increment the P register and continue. Or you might want to terminate by entering E@ . You can also display the contents of the instruction where the program terminated and try to determine the cause of the error. Since the error in this case is an integer overflow, you could look at the contents of the last three or four words in the stack when the error occurred. Usually, you will also look at your compilation listing. For this sample program, the listing of program MAIN is shown in Figure 4-2; the listing for SUBROUT and the PMAP listing from preparation are identical to those shown in Figure 3-1 in Section III since only program MAIN has been changed. :FORTRAN DBTEST2 PAGE 0001 HP32102B.00.0 00001000 $CONTROL MAP, LABEL,LOCATION,USLINIT 00012 00000200 PROGRAM MAIN 00012 00003000 CHARACTER*8 C,C1,C2(3) 00012 00004000 COMMON I4, I5 00012 00006000 DATA C/"DBTEST1"/ 00012 00007000 DATA C1 /"MAI NPROG"/, C2/"MONE", "MTWO", "MTHREE"/ 00012 00008000 DATA I6/ 1 0000 /,I7/700/,I8/800 / 00012 00009000 10 DISPLAY Cl,C2 00031 00010000 I1 = -1 00033 00011000 I2 = 1 00035 00012000 I3 = 10 00037 00013000 I4 = 100 00041 00014000 I5 = 1000 00043- 1 00014100 I5=32767+12 00046 00015000 DISPLAY "CALLING SUBROUTINE" 00101 00016000 20 CALL SUBROUT(C1,C2,11,12,13) 00111 00017000 DISPLAY "BACK FROM SUBROUTINE" 00143 00018000 STOP 00144 00019000 END SYMBOL MAP NAME TYPE STRUCTURE ADDRESS C CHARACTER SIMPLE VAR Q+ 1, I C1 CHARACTER SIMPLE VAR Q+ 2, I C2 CHARACTER ARRAY Q+ 2, I II INTEGER SIMPLE VAR Q+ 6 I2 INTEGER SIMPLE VAR Q+ 7 I3 INTEGER SIMPLE VAR Q+ 8 I4 INTEGER SIMPLE VAR 0 COMMON I5 INTEGER SIMPLE VAR 1 COMMON I6 INTEGER SIMPLE VAR 0+ 3, I I7 INTEGER SIMPLE VAR Q+ 4, I I8 INTEGER SIMPLE VAR Q+ 5, I SUBROUT SUBROUTINE COMMON BLOCKS NAME LENGTH COM' 2 LABEL MAP STATEMENT CODE STATEMENT CODE STATEMENT CODE LABEL OFFSET LABEL OFFSET LABEL OFFSET 10 12 20 101 Figure 4-2. Sample FORTRAN Program With Error Note item 1 in Figure 4-2. This location relative to the start of code location at 165 gives the PB-relative location 230. The program halted with the P register at 231 so this is the instruction containing the error. If you want to continue ignoring this error, enter: ?MR,P P 2:31 :233 ?R The program continues execution with the statement at location 46 + 165. Assuming there are no further errors, it will run until normal termination. You could also terminate the program by entering: ?E @ The program terminates with the message END OF PROGRAM and returns control to the operating system. If you want to display the contents of the statement causing the error, enter: ?DP-1,3 The three octal words of the instruction will be displayed. You can also display the contents of the stack at the time of the abort. The stack analysis showed that S, at this time, was at DB-relative location 52. Thus, to display the last three words in the stack at that time, enter: ?DDB+52-3,3 Depending on what you find, you may want to remove the values currently in the stack. You can do this with the E command as follows: ?E2 Remove 2 words from top of stack and resume, ?R Since the particular problems causing a program to abort vary widely, only suggestions can be given here of the particular action to take from among the many options provided through the DEBUG commands. USING SETDUMP INTRINSIC INTERACTIVELY You may include a call to the SETDUMP intrinsic anywhere within your program. If you want to transfer to DEBUG in case of an abort anywhere in the program, you should place the call at the beginning. If you only want DEBUG in case of an abort in a specific section of the program, place the intrinsic call at the beginning of this section and a call to RESETDUMP at the end. Used interactively, no parameters need be included in the intrinsic call since they will be ignored; control transfers to the DEBUG program exactly as if the :SETDUMP command had been entered in an interactive session as described above. If, however, the program may be executed in batch mode, you should include parameters to specify the portion of the stack you want dumped in case of an abort in a batch execution. These parameters are described below under the heading USING SETDUMP INTRINSIC IN A JOB.