Debug Tutorial: How to Examine Data

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print [ context ] [ format ] { expression | data_address } [ ,count ]
print [ context ] [ format ] -register_name
print [ context ] -reg
whatis [ context ] identifier

The debugger provides for the examination of data items in the program without having to insert print statements.

• print displays the value of a symbol or an expression.

• print with a structure name displays the value of each element in the structure.

• print with an array name displays the entire array from the beginning. Use ,count to control the number of elements printed.

• print with -reg switch or a specific register name switch displays the contents of the register(s).

• print with a simple, unparenthesized number assumes the number to be a data address and attempts to print the value stored at that address. Note: This is an anomaly which will be changed when the address command is functional.

• Format switches can be used to convert the form in which a value is displayed (available switches: d, o, x, l, s, a, f, F, m, M).

• whatis displays the data type for a given identifier.

• To get the data address of a variable, use '&' in C and 'LOC()' in Fortran.

Examples:

(all) > print l
***** (0) *****
 ** `bob.c`level3`53`l **
l = 3
***** (1) *****
 ** `bob.c`level1`68`l **
l = 1
***** (2) *****
 ** `bob.c`level2`60`l **
l = 2
(all) > print main`S1
***** (all) *****
 ** `bob.c`main`75`S1 **
struct AnyStruct {
    int  i1 = 1
    int  i2 = 0
    char  c1 = '\0000'
    char  * cPtr1 = 0x00000000
}
(all) > print(0) carry
***** (0) *****
 ** `bob.c`level3`53`carry **
  carry[0] = 'a'
  carry[1] = 'b'
  carry[2] = 'c'
  carry[3] = 'd'
  carry[4] = 'e'
(all) > print globalCharPtr
***** (all) *****
 ** `bob.c`main`101`globalCharPtr **
globalCharPtr = 0x008200e0
(all) > print *globalCharPtr
***** (all) *****
 ** `bob.c`main`101`*globalCharPtr **
*globalCharPtr = 'a'
(all) > print &ll
***** (all) *****
 ** `bob.c`main`101`&ll **
&ll = 0x7fc40434
(all) > whatis arry
***** (all) *****
int  arry[5][4]
(all) > whatis carry[0]
***** (all) *****
char
(all) > whatis S1
***** (all) *****
struct AnyStruct {
    int  i1;
    int  i2;
    char  c1;
    char  * cPtr1;
}
(all) > whatis level1i
***** (all) *****
int  level1(long )