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Evaluating and Displaying Data
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Assigning a Value to a Variable
Updated: June 2017
Oracle
®
Developer Studio 12.6: Debugging a Program with dbx
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Chapter 1 Getting Started With dbx
Compiling Your Code for Debugging
Starting dbx or dbxtool and Loading Your Program
Running Your Program in dbx
Debugging Your Program With dbx
Examining a Core File
Setting Breakpoints
Stepping Through Your Program
Looking at the Call Stack
Examining Variables
Finding Memory Access Problems and Memory Leaks
Quitting dbx
Accessing dbx Online Help
Chapter 2 Starting dbx
Starting a Debugging Session
Debugging a Core File
Debugging a Core File in the Same Operating Environment
If Your Core File Is Truncated
Debugging a Mismatched Core File
To Eliminate Shared Library Problems and Debug a Mismatched Core File
Using the Process ID
dbx Startup Sequence
Setting Startup Properties
Mapping the Compile-Time Directory to the Debug-Time Directory
Setting dbx Environment Variables
Creating Your Own dbx Commands
Compiling a Program for Debugging
Compiling With the –g Option
Using a Separate Debug File
How to Create a Separate Debug File
Ancillary Files (Oracle Solaris Only)
Compressed Debug Sections (Oracle Solaris Only)
Debugging Optimized Code
Parameters and Variables
Inlined Functions
Code Compiled Without the -g Option
Shared Libraries Require the -g Option for Full dbx Support
Completely Stripped Programs
Quitting Debugging
Stopping a Process Execution
Detaching a Process From dbx
Killing a Program Without Terminating the Session
Saving and Restoring a Debugging Run
Using the save Command
Saving a Series of Debugging Runs as Checkpoints
Restoring a Saved Run
Saving and Restoring Using replay
Chapter 3 Customizing dbx
Using the dbx Initialization File
Creating a .dbxrc File
Initialization File Sample
Setting dbxenv Variables
dbxenv Variables and the Korn Shell
Chapter 4 Viewing and Navigating To Code
Navigating To Code
Navigating To a File
Navigating To Functions
Selecting From a List of C++ Ambiguous Function Names
Choosing Among Multiple Occurrences
Printing a Source Listing
Walking the Call Stack to Navigate To Code
Types of Program Locations
Program Scope
Variables That Reflect the Current Scope
Visiting Scope
Components of the Visiting Scope
Changing the Visiting Scope
Qualifying Symbols With Scope Resolution Operators
Backquote Operator
C++ Double-Colon Scope Resolution Operator
Block Local Operator
Linker Names
Locating Symbols
Printing a List of Occurrences of a Symbol
Determining Which Symbol dbx Uses
Scope Resolution Search Path
Relaxing the Scope Lookup Rules
Viewing Variables, Members, Types, and Classes
Looking Up Definitions of Variables, Members, and Functions
Looking Up Definitions of Types and Classes
Debugging Information in Object Files and Executables
Object File Loading
Compiler and Linker Options to Support Debugging
Index DWARF (–xs[={yes|no}])
Separate Debug File (–z ancillary[=outfile])
Minimizing Debug Information
Listing Debugging Information for Modules
Listing Modules
Finding Source and Object Files
Chapter 5 Controlling Program Execution
Running a Program
Attaching dbx to a Running Process
Detaching dbx From a Process
Stepping Through a Program
Controlling Single Stepping Behavior
Stepping Into a Specific or Last Function
Continuing Execution of a Program
Calling a Function
Call Safety
Using Ctrl+C to Stop a Process
Event Management
Chapter 6 Setting Breakpoints and Traces
Setting Breakpoints
Setting a Breakpoint at a Line of Source Code
Setting a Breakpoint in a Function
Setting Multiple Breakpoints in C++ Programs
Setting Breakpoints in Member Functions of Different Classes
Setting Breakpoints in All Member Functions of a Class
Setting Multiple Breakpoints in Nonmember Functions
Setting Breakpoints in Objects
Setting Data Change Breakpoints (Watchpoints)
Stopping Execution When an Address Is Accessed
Stopping Execution When Variables Change
Stopping Execution on a Condition
Setting Filters on Breakpoints
Qualifying Breakpoints With Conditional Filters
Qualifying Breakpoints With Caller Filters
Filters and Multithreading
Tracing Execution
Setting a Trace
Controlling the Speed of a Trace
Directing Trace Output to a File
Executing dbx Commands at a Line
Setting Breakpoints in Dynamically Loaded Libraries
Listing and Deleting Breakpoints
Listing Breakpoints and Traces
Deleting Specific Breakpoints Using Handler ID Numbers
Enabling and Disabling Breakpoints
Efficiency Considerations
Chapter 7 Using the Call Stack
Finding Your Place on the Stack
Walking the Stack and Returning Home
Moving Up and Down the Stack
Moving Up the Stack
Moving Down the Stack
Moving to a Specific Frame
Popping the Call Stack
Hiding Stack Frames
Displaying and Reading a Stack Trace
Chapter 8 Evaluating and Displaying Data
Evaluating Variables and Expressions
Verifying Which Variable dbx Uses
Variables Outside the Scope of the Current Function
Printing the Value of a Variable, Expression, or Identifier
Printing C++ Pointers
Evaluating Unnamed Arguments in C++ Programs
Dereferencing Pointers
Monitoring Expressions
Stop the Display (Undisplaying)
Assigning a Value to a Variable
Evaluating Arrays
Array Slicing
Array Slicing Syntax for C and C++
Array Slicing Syntax for Fortran
Using Slices
Using Strides
Using Pretty-Printing
Invoking Pretty-Printing
Call-Based Pretty-Printing
Pretty-Printing Function Considerations
Possible Failures
Python Pretty-Print Filters
Using Python
Python Pretty-Print API Documentation
Chapter 9 Using Runtime Checking
Capabilities of Runtime Checking
When to Use Runtime Checking
Runtime Checking Requirements
Using Runtime Checking
Enabling Memory Use and Memory Leak Checking
Enabling Memory Access Checking
Enabling Hardware Assisted Checking
Enabling All Runtime Checking
Disabling Runtime Checking
Running Your Program
Using Access Checking
Understanding the Memory Access Error Report
Memory Access Errors
Using Memory Leak Checking
Detecting Memory Leak Errors
Possible Leaks
Checking for Leaks
Understanding the Memory Leak Report
Generating a Leak Report
Combining Leaks
Fixing Memory Leaks
Using Memory Use Checking
Suppressing Errors
Types of Suppression
Suppression by Scope and Type
Suppression of Last Error
Limiting the Number of Errors Reported
Suppressing Error Examples
Default Suppressions
Using Suppression to Manage Errors
Using Runtime Checking on a Child Process
Using Runtime Checking on an Attached Process
Attached Process on a System Running Oracle Solaris
Attached Process on a System Running Linux
Using Fix and Continue With Runtime Checking
Runtime Checking Application Programming Interface
Using Runtime Checking in Batch Mode
bcheck Syntax
bcheck Examples
Enabling Batch Mode Directly From dbx
Troubleshooting Tips
Runtime Checking Limitations
Performance Improves With More Symbols and Debug Information
SIGSEGV and SIGALTSTACK Signals Are Restricted on x86 Platforms
Performance Improves When Sufficient Patch Area Is Available Within 8 MB of All Existing Code (SPARC Platforms Only).
Runtime Checking Errors
Access Errors
Bad Free (baf) Error
Duplicate Free (duf) Error
Misaligned Free (maf) Error
Misaligned Read (mar) Error
Misaligned Write (maw) Error
Out of Memory (oom) Error
Read From Array Out-of-Bounds (rob) Error
Read From Unallocated Memory (rua) Error
Read From Uninitialized Memory (rui) Error
Write to Array Out-of-Bounds Memory (wob) Error
Write to Read-Only Memory (wro) Error
Write to Unallocated Memory (wua) Error
Memory Leak Errors
Address in Block (aib) Error
Address in Register (air) Error
Memory Leak (mel) Error
Chapter 10 Debugging Multithreaded Applications
Understanding Multithreaded Debugging
Thread Information
Thread and LWP States
Viewing the Context of Another Thread
Viewing the Threads List
Resuming Execution
Understanding Thread Creation Activity
Understanding LWP Information
Chapter 11 Debugging Child Processes
Attaching to Child Processes
Following the exec Function
Following the fork Function
Interacting With Events
Chapter 12 Debugging OpenMP Programs
How Compilers Transform OpenMP Code
dbx Functionality Available for OpenMP Code
Single-Stepping Into a Parallel Region
Printing Variables and Expressions
Printing Region and Thread Information
Serializing the Execution of a Parallel Region
Using Stack Traces
Using the dump Command
Using Events
Synchronization Events
Other Events
Execution Sequence of OpenMP Code
Chapter 13 Working With Signals
Understanding Signal Events
Catching Signals
Changing the Default Signal Lists
Trapping the FPE Signal (Oracle Solaris Only)
Determining Where the Exception Occurred
Determining the Cause of the Exception
Sending a Signal to a Program
Automatically Handling Signals
Chapter 14 Debugging C++ With dbx
Using dbx With C++
Exception Handling in dbx
Commands for Handling Exceptions
exception Command
intercept Command
unintercept Command
whocatches Command
Examples of Exception Handling
Debugging With C++ Templates
Template Example
Commands for C++ Templates
whereis Command
whatis Command
stop inclass Command
stop infunction Command
stop in Command
call Command
print Expressions
list Expressions
Chapter 15 Debugging Fortran Using dbx
Debugging Fortran
Current Procedure and File
Uppercase Letters
Sample dbx Session
How to Run the Sample dbx Session
Debugging Segmentation Faults
Using dbx to Locate Problems
Locating Exceptions
Tracing Calls
Working With Arrays
Fortran Allocatable Arrays
Showing Intrinsic Functions
Showing Complex Expressions
Showing Interval Expressions
Showing Logical Operators
Viewing Fortran Derived Types
Pointer to Fortran Derived Type
Object Oriented Fortran
Allocatable Scalar Type
Chapter 16 Debugging a Java Application With dbx
Using dbx With Java Code
Capabilities of dbx With Java Code
Limitations of dbx With Java Code
Environment Variables for Java Debugging
Starting to Debug a Java Application
Debugging a Class File
Debugging a JAR File
Debugging a Java Application That Has a Wrapper
Attaching dbx to a Running Java Application
To Attach to a Running Java Process
Debugging a C Application or C++ Application That Embeds a Java Application
Passing Arguments to the JVM Software
Specifying the Location of Your Java Source Files
Specifying the Location of Your C Source Files or C++ Source Files
Specifying a Path for Class Files That Use Custom Class Loaders
Setting Breakpoints on Java Methods
Setting Breakpoints in Native (JNI) Code
Customizing Startup of the JVM Software
Specifying a Path Name for the JVM Software
Passing Run Arguments to the JVM Software
Specifying a Custom Wrapper for Your Java Application
Using a Custom Wrapper That Accepts Command-Line Options
Using a Custom Wrapper That Does Not Accept Command-Line Options
Specifying 64-bit JVM Software
dbx Modes for Debugging Java Code
Switching From Java or JNI Mode to Native Mode
Switching Modes When You Interrupt Execution
Using dbx Commands in Java Mode
Java Expression Evaluation in dbx Commands
Static and Dynamic Information Used by dbx Commands
Commands With Identical Syntax and Functionality in Java Mode and Native Mode
Commands With Different Syntax in Java Mode
Commands Valid Only in Java Mode
Chapter 17 Debugging at the Machine-Instruction Level
Using dbx at the Machine-Instruction Level
Examining the Contents of Memory
Using the examine or x Command
Using Addresses
Using Formats
Using Count
Examples of Using an Address
Using the dis Command
Using the listi Command
Stepping and Tracing at Machine-Instruction Level
Single-Stepping at the Machine-Instruction Level
Tracing at the Machine-Instruction Level
Setting Breakpoints at the Machine-Instruction Level
Setting a Breakpoint at an Address
Using the regs Command
Platform-Specific Registers
SPARC Register Information
x86 Register Information
AMD64 Register Information
Chapter 18 Using dbx With the Korn Shell
ksh-88 Features Not Implemented
Extensions to ksh-88
Renamed Commands
Rebinding of Editing Functions
Chapter 19 Debugging Shared Libraries
Dynamic Linker
Link Map
Startup Sequence and .init Sections
Procedure Linkage Tables
Setting Breakpoints in Shared Libraries
Setting a Breakpoint in an Explicitly Loaded Library
Appendix A Modifying a Program State
Impacts of Running a Program Under dbx
Commands That Alter the State of the Program
assign Command
pop Command
call Command
print Command
when Command
fix Command
cont at Command
Appendix B Event Management
Event Handlers
Creating Event Handlers
Manipulating Event Handlers
Using Event Counters
Event Safety
Setting Event Specifications
Breakpoint Event Specifications
in Event Specification
at Event Specification
infile Event Specification
infunction Event Specification
inmember Event Specification
inmethod Event Specification
inclass Event Specification
inobject Event Specification
Data Change Event Specifications
access Event Specification
change Event Specification
cond Event Specification
System Event Specifications
dlopen and dlclose Event Specification
fault Event Specification
lwp_exit Event Specification
sig Event Specification
sysin Event Specification
sysout Event Specification
sysin | sysout Event Specifications
Execution Progress Event Specifications
exit Event Specification
next Event Specification
returns Event Specification
step Event Specification
throw Event Specification
Tracked Thread Event Specifications
omp_barrier Event Specification
omp_taskwait Event Specification
omp_ordered Event Specification
omp_critical Event Specification
omp_atomic Event Specification
omp_flush Event Specification
omp_task Event Specification
omp_master Event Specification
omp_single Event Specification
Other Event Specifications
attach Event Specification
detach Event Specification
lastrites Event Specification
proc_gone Event Specification
prog_new Event Specification
stop Event Specification
sync Event Specification
syncrtld Event Specification
thr_create [thread-ID] Event Specification
thr_exit Event Specification
timer Event Specification
Event Specification Modifiers
-if Modifier
-resumeone Modifier
-in Modifier
-disable Modifier
-count n, -count infinity Modifier
-temp Modifier
-instr Modifier
-thread Modifier
-lwp Modifier
-hidden Modifier
-perm Modifier
Parsing and Ambiguity
Using Predefined Variables
Variables Valid for when Command
$handlerid
Variables Valid for when Command and Specific Events
Event Handler Examples
Setting a Breakpoint for Store to an Array Member
Implementing a Simple Trace
Enabling a Handler While Within a Function
Determining the Number of Lines Executed
Determining the Number of Instructions Executed by a Source Line
Enabling a Breakpoint After an Event Occurs
Resetting Application Files for replay
Checking Program Status
Catch Floating-Point Exceptions
Appendix C Macros
Additional Uses of Macro Expansion
Macro Definitions
Compiler and Compiler Options
Tradeoffs in Functionality
Limitations
Skimming Errors
Using the pathmap Command to Improve Skimming
Appendix D Command Reference
adi assign Command
Native Mode Syntax
adi examine Command
Native Mode Syntax
assign Command
Native Mode Syntax
Java Mode Syntax
attach Command
Syntax
bsearch Command
Syntax
call Command
Native Mode Syntax
Java Mode Syntax
cancel Command
catch Command
Syntax
check Command
Syntax
–access Option
–leaks Option
–memuse Option
–all Option
clear Command
Syntax
collector Command
Syntax
collector archive Command
Syntax
collector dbxsample Command
Syntax
collector disable Command
collector enable Command
collector heaptrace Command
Syntax
collector hwprofile Command
Syntax
collector limit Command
Syntax
collector pause Command
collector profile Command
Syntax
collector resume Command
collector sample Command
Syntax
collector show Command
Syntax
collector status Command
collector store Command
Syntax
collector synctrace Command
Syntax
collector tha Command
Syntax
collector version Command
Syntax
cont Command
Syntax
dalias Command
Syntax
dbx Command
Native Mode Syntax
Java Mode Syntax
Options
dbxenv Command
Syntax
debug Command
Native Mode Syntax
Java Mode Syntax
Options
delete Command
Syntax
detach Command
Native Mode Syntax
Java Mode Syntax
dis Command
Syntax
Options
display Command
Native Mode Syntax
Java Mode Syntax
down Command
Syntax
dump Command
Syntax
edit Command
Syntax
examine Command
Syntax
exception Command
Syntax
exists Command
Syntax
file Command
Syntax
files Command
Native Mode Syntax
Java Mode Syntax
fix Command
Syntax
fixed Command
fortran_modules Command
Syntax
frame Command
Syntax
func Command
Native Mode Syntax
Java Mode Syntax
funcs Command
Syntax
gdb Command
Syntax
handler Command
Syntax
hide Command
Syntax
ignore Command
Syntax
import Command
Syntax
intercept Command
Syntax
java Command
Syntax
jclasses Command
Syntax
joff Command
jon Command
jpkgs Command
kill Command
Syntax
language Command
Syntax
line Command
Syntax
Examples
list Command
Syntax
Options
Examples
listi Command
loadobject Command
Syntax
loadobject -dumpelf Command
Syntax
loadobject -exclude Command
Syntax
loadobject -hide Command
Syntax
loadobject -list Command
Syntax
loadobject -load Command
Syntax
loadobject -unload Command
Syntax
loadobject -use Command
Syntax
lwp Command
Syntax
lwps Command
macro Command
Syntax
mmapfile Command
Syntax
Example
module Command
Syntax
modules Command
Syntax
native Command
Syntax
next Command
Native Mode Syntax
Java Mode Syntax
nexti Command
Syntax
omp_loop Command
omp_pr Command
Syntax
omp_serialize Command
Syntax
omp_team Command
Syntax
omp_tr Command
Syntax
pathmap Command
Syntax
Examples
pop Command
Syntax
print Command
Native Mode Syntax
Java Mode Syntax
proc Command
Syntax
prog Command
Syntax
python-docs Command
Syntax
quit Command
Syntax
regs Command
Syntax
Example (SPARC platform)
replay Command
Syntax
rerun Command
Syntax
restore Command
Syntax
rprint Command
Syntax
rtc showmap Command
rtc skippatch Command
Syntax
run Command
Native Mode Syntax
Java Mode Syntax
runargs Command
Syntax
save Command
Syntax
scopes Command
search Command
Syntax
showblock Command
Syntax
showleaks Command
Syntax
showmemuse Command
Syntax
source Command
Syntax
status Command
Syntax
Example
step Command
Native Mode Syntax
Java Mode Syntax
stepi Command
Syntax
stop Command
Syntax
Native Mode Syntax
Java Mode Syntax
stopi Command
Syntax
suppress Command
Syntax
sync Command
Syntax
syncs Command
thread Command
Native Mode Syntax
Java Mode Syntax
threads Command
Native Mode Syntax
Java Mode Syntax
trace Command
Syntax
Native Mode Syntax
Java Mode Syntax
tracei Command
Syntax
uncheck Command
Syntax
undisplay Command
Native Mode Syntax
Java Mode Syntax
unhide Command
Syntax
unintercept Command
Syntax
unsuppress Command
Syntax
unwatch Command
Syntax
up Command
Syntax
use Command
watch Command
Syntax
whatis Command
Native Mode Syntax
Java Mode Syntax
when Command
Syntax
Native Mode Syntax
Java Mode Syntax
wheni Command
Syntax
where Command
Native Mode Syntax
Java Mode Syntax
whereami Command
Syntax
whereis Command
Syntax
which Command
Syntax
whocatches Command
Syntax
Index
Index Numbers and Symbols
Index A
Index B
Index C
Index D
Index E
Index F
Index G
Index H
Index I
Index J
Index K
Index L
Index M
Index N
Index O
Index P
Index Q
Index R
Index S
Index T
Index U
Index V
Index W
Index X
Language:
English
Assigning a Value to a Variable
Use the
assign
command to assign a value to a variable:
assign
variable
=
expression
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