notes

gdb

Sample code debug-test.c\\
, https://peteolson.me/uploads/gdb.pdf|gdb cheat sheet
, 
, 
, <code>
, #include <stdio.h>
, 
, int main () 
, {
, 	int a = 2;
, 	// infinite loop, i will always be equal to or greater then zero 
, 	for(int i = 0; i >= 0; i++)
, 	{
, 		printf(DQ\n%d DQ, i);
, 	}
, 	return 0;
, }
, 
, </code>
, <code>
, 
, 
, Source file needs to be compiled with the g option.
, Compile debug-test.c:
, gcc -o -g debug-test debug-test.c
, 
, Start the debugger:
, (command line) gdb ./debug-test
, 
, Use the layout:
, (gdb) layout next
, 
, Set a breakpoint at function main:
, (gdb) break main
, 
, Start / run:
, (gdb) run
, 
, Watch a variable:
, watch (variable)
, 
, Next:
, (gdb) n
, 
, 
, 
, </code>
, <code>
, GDB offers a big list of commands, however the following commands are the ones used most frequently:
, 
, b main - Puts a breakpoint at the beginning of the program
, 
, b - Puts a breakpoint at the current line
, 
, b N - Puts a breakpoint at line N
, 
, b +N - Puts a breakpoint N lines down from the current line
, 
, b fn - Puts a breakpoint at the beginning of function DQfnDQ
, 
, d N - Deletes breakpoint number N
, 
, info break - list breakpoints
, 
, r - Runs the program until a breakpoint or error
, 
, c - Continues running the program until the next breakpoint or error
, 
, f - Runs until the current function is finished
, 
, s - Runs the next line of the program
, 
, s N - Runs the next N lines of the program
, 
, n - Like s, but it does not step into functions
, 
, u N - Runs until you get N lines in front of the current line
, 
, p var - Prints the current value of the variable DQvarDQ
, 
, bt - Prints a stack trace
, 
, u - Goes up a level in the stack
, 
, d - Goes down a level in the stack
, 
, q - Quits gdb
, </code>