Breakpoints pause execution so you can inspect state. Set at a line, function, or condition.
(gdb) break main # breakpoint at function 'main' (gdb) break file.c:10 # breakpoint at line 10 in file.c (gdb) break file.c:10 if x > 5 # conditional: pause only if x > 5 (gdb) info breakpoints # list all breakpoints (gdb) delete 1 # delete breakpoint 1 (gdb) disable 1 # disable (don't stop, keep it) (gdb) enable 1 # enable (gdb) continue # resume from breakpoint
When a breakpoint hits, GDB shows the line and pauses. You can then inspect variables, print expressions, step through code, etc.
Conditional breakpoints are powerful: break file.c:10 if x > 5 pauses only when the condition is true. Avoids stopping hundreds of times if the issue is only when x is large.
Breakpoint numbers start at 1 (shown by info breakpoints). Reference by number to delete, disable, or enable. Temporarily disable instead of delete if you might need the breakpoint later.
Watch points (watch variable) pause when a variable changes value—useful for finding where a variable gets corrupted. Set with watch x (pause when x changes).
Display commands (display x) print a variable every time execution pauses. Useful for monitoring value changes across stepping.
Clear all breakpoints: delete (without arguments).