Thread: gdb breakpoints

In order to understand a program for data compression, I'm trying to step through a program using GDB, and am having a problem setting a breakpoint.The code is all in a single directory, and the Makefile is as follows:

Code:

############################################################################
#
# Makefile for huffman encode/decode programs
# 
############################################################################


CC = gcc
LD = gcc
CFLAGS = -ggdb -O3 -Wall -Wextra -ansi -pedantic -c
LDFLAGS = -O3 -o


# libraries
LIBS = -L. -lhuffman -loptlist


# Treat NT and non-NT windows the same
ifeq ($(OS),Windows_NT)
	OS = Windows
endif


ifeq ($(OS),Windows)
	EXE = .exe
	DEL = del
else	#assume Linux/Unix
	EXE =
	DEL = rm
endif


all:		sample$(EXE)


sample$(EXE):	sample.o libhuffman.a liboptlist.a
		$(LD) $^ $(LIBS) $(LDFLAGS) $@


sample.o:	sample.c huffman.h optlist.h
		$(CC) $(CFLAGS) $<


libhuffman.a:	huffman.o canonical.o huflocal.o bitarray.o bitfile.o
		ar crv libhuffman.a huffman.o canonical.o huflocal.o\
		bitarray.o bitfile.o
		ranlib libhuffman.a


huffman.o:	huffman.c huflocal.h bitarray.h bitfile.h
		$(CC) $(CFLAGS) $<


canonical.o:	canonical.c huflocal.h bitarray.h bitfile.h
		$(CC) $(CFLAGS) $<


huflocal.o:	huflocal.c huflocal.h
		$(CC) $(CFLAGS) $<


bitarray.o:	bitarray.c bitarray.h
		$(CC) $(CFLAGS) $<


bitfile.o:	bitfile.c bitfile.h
		$(CC) $(CFLAGS) $<


liboptlist.a:	optlist.o
		ar crv liboptlist.a optlist.o
		ranlib liboptlist.a


optlist.o:	optlist.c optlist.h
		$(CC) $(CFLAGS) $<


clean:
		$(DEL) *.o
		$(DEL) *.a
		$(DEL) sample$(EXE)

I'd like to set a breakpoint to step through HuffmanEncodeFile(), which is found in huffman.c:90 and called at sample.c:210
When I try running gdb with such a breakpoint, I get the following terminal output:

Code:

Breakpoint 3 at 0x8048ca0<function, no debug info> HuffmanEncodeFile;

I've checked the manual (which I'm not real clear on), and given a try to hbreak, but that didn't help.
Do I have to make any changes to Makefile? Am I writing my breakpoints incorrectly?

[I'm using a virtual machine running linux, with a clang compiler, if that matters]

Originally Posted by migf1

Try adding the -g3 option at the compilation command-line.
E.g.

Code:

 gcc -g3 ...

Actually, you can copy your makefile to a debugging version, with all -O3's replaced by -g3's

No luck. With your first suggestion, I get terminal output of:

Code:

jharvard@appliance (~/Dropbox/huffman): makegcc sample.o libhuffman.a liboptlist.a -L. -lhuffman -loptlist -03 -o sample
gcc: error: unrecognized command line option '-03'

and with the second:

Code:

Breakpoint 1 at 0x8048789: file sample.c, line 83.
(gdb) b huffman.c:90
No source file named huffman.c.

Perhaps I should mention that other files that I have upon which gdb functions properly are compiled with clang, rather than gcc. Would this make any difference?

I'll take a look & see if anything works. So far I've tried redoing Makefile in all sorts of combos, and remade file, but still not the right combo. Maybe the links will help.

finally got the right combination of switches in Makefile to allow gdb to function:

Code:

#############################################################################
# Makefile for huffman encode/decode programs
#
############################################################################


CC = gcc -g3
LD = gcc
CFLAGS = -ggdb -O3 -Wall -Wextra -ansi -pedantic -c
LDFLAGS = -O3 -o

Thanks to all for your persistence & help