WAGO 750 Series Manual page 128

124 • Step-by-Step Guide to your own Linux Application
Debugging of User Space Programs
GDB command Description
break
list
print i
display i
undisplay
whatis i
backtrace
where
set var
i = ?
help.
quit
exit
run
Debugging via the console is not a very convenient way of doing it, however,
it offers a very good opportunity to control user space programs of the Linux
fieldbus controller via a PC.
Sets a breakpoint.
break
newProg.c:20
break main
break *0x00dd8080
Lists ten code lines around the current position of the program counter.
Another list call will list the next ten lines.
list newProc.c:15 lists ten lines around line 15 in the newProg.c file
Displays the current value of the i variable.
print *pi displays the content of the memory area the pointer pi points to.
Displays the current value of the i variable. The value or the values are
updated after every execution of code (step, next, continue).
Undisplays the value that was displayed via the display call before
Displays the data type of the i variable.
Displays the calling functions and their parameter values from the stack.
Displays the content of the stack like backtrace.
set var i = 5 sets the i variable to 5.
Displays help texts for the available commands.
help continue, for example, displays a help text for continue,
help set displays the help text for set
Terminates the remote program
Exit the debugger.
run call is not possible. The program counter is set to 0x00000000 which,
with the type of CPU used (without MMU), will lead to a restart of the
Linux fieldbus controller.
Sets a breakpoint at line 20 in the main.c file
Sets a breakpoint at the main function start
Sets a breakpoint at the indicated address in the
program code
WAGO-I/O-SYSTEM 750
Linux Fieldbus Coupler