#makefileCC=gcc
CXX=g++
RM=rm -f
CPPFLAGS=-g
LDFLAGS=-g
LDLIBS=
AR=arSRCS=main.cc functions.cc
OBJS=$(subst .cc,.o,$(SRCS))all: main
main: $(OBJS)$(CXX) $(LDFLAGS) -o main $(OBJS) -L. $(LDLIBS) main.o: main.cc functions.h testobj.hfunctions.o: functions.h functions.ccclean:$(RM) $(OBJS)all-clean: clean$(RM) main

 1 #include<iostream>
 2 #include"functions.h"
 5 int main()
 6 {
 7 std::cout << "Enter two numbers:" << std::endl;
 8 int v1 = 0, v2 = 0;
 9 std::cin >> v1 >> v2;
10 std::cout << "The sum of " << v1 << " and " << v2
11 << " is " << v1 + v2 << std::endl;
12
13 function();
14
15 return 0;
16 }

1 #include<iostream>
2 int function(void)
3 {
4     std::cout << "I am in a function!" << std::endl;
5     return 0;
6 }

1 int function(void);

调试结果如下：solidmango@solidmango-pc:~/testmake/Test_L1$ gdb main
GNU gdb (Ubuntu 7.7-0ubuntu3) 7.7
Copyright (C) 2014 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
Reading symbols from main...done.(gdb) b 2 //在第二行设置断点
Breakpoint 1 at 0x400a4a: file main.cc, line 2.
(gdb) r //全速运行
Starting program: /home/solidmango/testmake/Test_L1/mainBreakpoint 1, main () at main.cc:7
7    std::cout << "Enter two numbers:" << std::endl;//断点命中
(gdb) s
Enter two numbers:
8    int v1 = 0, v2 = 0;
(gdb) s //单步执行
9    std::cin >> v1 >> v2;
(gdb) n
5
6
11    << " is " << v1 + v2 << std::endl;
(gdb) s
10    std::cout << "The sum of " << v1 << " and " << v2
(gdb) s
11    << " is " << v1 + v2 << std::endl;
(gdb) s
The sum of 5 and 6 is 11
14    function();
(gdb)

#makefile
CC=gcc
CXX=g++
RM=rm -f
CPPFLAGS=-g
LDFLAGS=-g
LDLIBS=-ltest #changed
AR=arSRCS=main.cc functions.cc
OBJS=$(subst .cc,.o,$(SRCS))all: main
main: $(OBJS) libtest.a #changed

$(CXX) $(LDFLAGS) -o main $(OBJS) -L. $(LDLIBS) main.o: main.cc functions.h testobj.h functions.o: functions.h functions.cc 

clean: $(RM) $(OBJS) 

all-clean: clean $(RM) main

#include<iostream>
#include"functions.h"
#include"testobj.h"int main()
{
std::cout << "Enter two numbers:" << std::endl;
int v1 = 0, v2 = 0;
std::cin >> v1 >> v2;
std::cout << "The sum of " << v1 << " and " << v2
<< " is " << v1 + v2 << std::endl;function();TestObj();return 0;
}

#include<iostream>
int TestObj(void)
{std::cout << "I am in TestObj!" << std::endl;return 0;
}

int TestObj(void);

solidmango@solidmango-pc:~/testmake/Test_L1$ g++ -g -c -o testobj.o testobj.cc
solidmango@solidmango-pc:~/testmake/Test_L1$ ar rv libtest.a testobj.o
ar: creating libtest.a
a - testobj.o
solidmango@solidmango-pc:~/testmake/Test_L1$ make
g++  -g  -c -o main.o main.cc
g++  -g  -c -o functions.o functions.cc
g++ -g -o main main.o functions.o -L. -ltest
solidmango@solidmango-pc:~/testmake/Test_L1$ ./main
Enter two numbers:
5
6
The sum of 5 and 6 is 11
I am in a function!
I am in TestObj!
solidmango@solidmango-pc:~/testmake/Test_L1$ 

g++ -g -c -fPIC -o testobj.o testobj.cc
g++ -g  -shared -o libtest.so testobj.o
sudo cp libtest.so /lib/libtest.so

CC=gcc
CXX=g++
RM=rm -f
CPPFLAGS=-g
LDFLAGS=-g
LDLIBS=-ltest
AR=arSRCS=main.cc functions.cc
OBJS=$(subst .cc,.o,$(SRCS))all: main
main: $(OBJS) libtest.so$(CXX) $(LDFLAGS) -o main $(OBJS) -L. $(LDLIBS) main.o: main.cc functions.h testobj.hfunctions.o: functions.h functions.ccclean:$(RM) $(OBJS)all-clean: clean$(RM) main

调试结果如下：solidmango@solidmango-pc:~/testmake/Test_L1$ gdb main
GNU gdb (Ubuntu 7.7-0ubuntu3) 7.7
Copyright (C) 2014 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from main...done.
(gdb) b TestObj
Breakpoint 1 at 0x400910
(gdb) r
Starting program: /home/solidmango/testmake/Test_L1/main
Enter two numbers:
7
8
The sum of 7 and 8 is 15
I am in a function!Breakpoint 1, 0x0000000000400910 in TestObj()@plt ()
(gdb) s
Single stepping until exit from function _Z7TestObjv@plt,
which has no line number information.
TestObj () at testobj.cc:3
3   {
(gdb) bt
#0  TestObj () at testobj.cc:3
#1  0x0000000000400b05 in main () at main.cc:17
(gdb) info sharedlibrary
From                To                  Syms Read   Shared Object Library
0x00007ffff7ddaae0  0x00007ffff7df54e0  Yes         /lib64/ld-linux-x86-64.so.2
0x00007ffff7bd8850  0x00007ffff7bd89c5  Yes         /lib/libtest.so
0x00007ffff792f5c0  0x00007ffff799299a  Yes (*)     /usr/lib/x86_64-linux-gnu/libstdc++.so.6
0x00007ffff752d4a0  0x00007ffff7673413  Yes         /lib/x86_64-linux-gnu/libc.so.6
0x00007ffff720d610  0x00007ffff727c1b6  Yes         /lib/x86_64-linux-gnu/libm.so.6
0x00007ffff6ff4ab0  0x00007ffff7004995  Yes (*)     /lib/x86_64-linux-gnu/libgcc_s.so.1
(*): Shared library is missing debugging information.
(gdb) list
1   #include<iostream>
2   int TestObj(void)
3   {
4       std::cout << "I am in TestObj!" << std::endl;
5       return 0;
6   }
(gdb)