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Command Summary

The following tables of commands should be enough to get you started.

 
Starting and Stopping
 
Command Description Example
run Run the program from scratch run
step Step on one source statement. If it calls a function step into the function step
next Step on one source statement. If it calls a function step over the function next
cont Resume program execution (after Ctrl-C or breakpoint) cont
Ctrl-C Interrupt a running program Ctrl-C
quit Exit gdb quit

 
Breakpoints i.e. Places where debugger will suspend execution
 
Command Description Example
break main Break when main program starts break main
break function Break when function entered break Animal::Talk
break file:line Break when source line reached break Animal.cxx:7
break line Break when line in current source reached break 7
info break List current breakpoints info break
delete n Delete breakpoint n (omit n for all) delete 3
disable n Disable breakpoint n (omit n for all) delete 3
enable n Enable breakpoint n (omit n for all) delete 3

 
Examining the current execution point
 
Command Description Example
info stack List the stack i.e. list of active callers from current point back to main program info stack
up Move up the stack to the caller of the current function up
down Move down the stack to the callee of the current function down
list List a few source lines round the current instruction list
list n List a few source lines round source line n list 20
list - List the previous few source lines list -

 
Examining and modifying variables
 
Command Description Example
print expr Print the value of an expression. Normally the expression is just the name of a variable print fSound
print *var Print the value pointed to by variable print *this
setvar = expr Set variable equal to expression set fAge = 57


next up previous contents
Next: Example: Debugging the Zoo Up: Using the gdb Debugger Previous: Typing Commands and Getting   Contents
P.D. Gronbech (IT Staff) 2015-10-02