[已解决]虚拟机ubuntu下gdb调试出现的问题

梦回连营

1. #include <iostream>
   
2. 
   
3. using namespace std;
   
4. 
   
5. int main(void) {
   
6.     cout << "hello world" << endl;
   
7.     return 0;
   
8. }

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在使用gdb调试以上代码的时侯， 运行到最后一个花括号上出现了下列的报错信息，是怎么情况？

1. __libc_start_main (main=0x5555555551a9 <main()>, argc=1, argv=0x7fffffffdf98,
   
2.     init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>,
   
3.     stack_end=0x7fffffffdf88) at ../csu/libc-start.c:342
   
4. 342        ../csu/libc-start.c: No such file or directory.
   

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最佳答案

月排行榜 / 总排行榜

人造人

2022-2-3 16:07:00

你用的是单步步入指令 s 吧
这会在最后让程序停在调用 main 函数的下一条语句
main 函数是在 libc-start.c 文件中调用的，你用 s 指令就返回到这个文件了
一般 gcc 不提供这个文件，当然就找不到了
这不算是错误
你可以自己编译 gcc 的源代码，这个文件在 gcc 的源代码中
要在源代码级别调试库函数，你需要自己编译一个带源代码版本且不开优化的 gcc 编译器，当然还有依赖的库

1. # gdb main
   
2. GNU gdb (GDB) 10.2
   
3. Copyright (C) 2021 Free Software Foundation, Inc.
   
4. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
   
5. This is free software: you are free to change and redistribute it.
   
6. There is NO WARRANTY, to the extent permitted by law.
   
7. Type "show copying" and "show warranty" for details.
   
8. This GDB was configured as "x86_64-pc-linux-gnu".
   
9. Type "show configuration" for configuration details.
   
10. For bug reporting instructions, please see:
    
11. <https://www.gnu.org/software/gdb/bugs/>.
    
12. Find the GDB manual and other documentation resources online at:
    
13.     <http://www.gnu.org/software/gdb/documentation/>.
    
14. 
    
15. For help, type "help".
    
16. Type "apropos word" to search for commands related to "word"...
    
17. Reading symbols from main...
    
18. (gdb) b main
    
19. Breakpoint 1 at 0x4011ac: file main.cpp, line 6.
    
20. (gdb) r
    
21. Starting program: /tmp/main
    
22. warning: File "/usr/lib/libstdc++.so.6.0.29-gdb.py" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
    
23. To enable execution of this file add
    
24.         add-auto-load-safe-path /usr/lib/libstdc++.so.6.0.29-gdb.py
    
25. line to your configuration file "/root/.gdbinit".
    
26. To completely disable this security protection add
    
27.         set auto-load safe-path /
    
28. line to your configuration file "/root/.gdbinit".
    
29. For more information about this security protection see the
    
30. "Auto-loading safe path" section in the GDB manual.  E.g., run from the shell:
    
31.         info "(gdb)Auto-loading safe path"
    
32. 
    
33. Breakpoint 1, main () at main.cpp:6
    
34. 6            cout << "hello world" << endl;
    
35. (gdb) n
    
36. hello world
    
37. 7            return 0;
    
38. (gdb) s
    
39. 8        }
    
40. (gdb) s
    
41. __libc_start_main (main=0x4011a8 <main()>, argc=1, argv=0x7fffffffeae8, init=0x401222 <__libc_csu_init>,
    
42.     fini=0x40129a <__libc_csu_fini>, rtld_fini=0x7ffff7fd32b6 <_dl_fini>, stack_end=0x7fffffffead8)
    
43.     at ../csu/libc-start.c:366
    
44. 366          exit (result);
    
45. (gdb) l
    
46. 361        #else
    
47. 362          /* Nothing fancy, just call the function.  */
    
48. 363          result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
    
49. 364        #endif
    
50. 365       
    
51. 366          exit (result);
    
52. 367        }
    
53. (gdb)

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1. # gdb main
   
2. GNU gdb (GDB) 10.2
   
3. Copyright (C) 2021 Free Software Foundation, Inc.
   
4. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
   
5. This is free software: you are free to change and redistribute it.
   
6. There is NO WARRANTY, to the extent permitted by law.
   
7. Type "show copying" and "show warranty" for details.
   
8. This GDB was configured as "x86_64-pc-linux-gnu".
   
9. Type "show configuration" for configuration details.
   
10. For bug reporting instructions, please see:
    
11. <https://www.gnu.org/software/gdb/bugs/>.
    
12. Find the GDB manual and other documentation resources online at:
    
13.     <http://www.gnu.org/software/gdb/documentation/>.
    
14. 
    
15. For help, type "help".
    
16. Type "apropos word" to search for commands related to "word"...
    
17. Reading symbols from main...
    
18. (gdb) b main
    
19. Breakpoint 1 at 0x4011ac: file main.cpp, line 6.
    
20. (gdb) r
    
21. Starting program: /tmp/main
    
22. warning: File "/usr/lib/libstdc++.so.6.0.29-gdb.py" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
    
23. To enable execution of this file add
    
24.         add-auto-load-safe-path /usr/lib/libstdc++.so.6.0.29-gdb.py
    
25. line to your configuration file "/root/.gdbinit".
    
26. To completely disable this security protection add
    
27.         set auto-load safe-path /
    
28. line to your configuration file "/root/.gdbinit".
    
29. For more information about this security protection see the
    
30. "Auto-loading safe path" section in the GDB manual.  E.g., run from the shell:
    
31.         info "(gdb)Auto-loading safe path"
    
32. 
    
33. Breakpoint 1, main () at main.cpp:6
    
34. 6            cout << "hello world" << endl;
    
35. (gdb) n
    
36. hello world
    
37. 7            return 0;
    
38. (gdb) s
    
39. 8        }
    
40. (gdb) s
    
41. __libc_start_main (main=0x4011a8 <main()>, argc=1, argv=0x7fffffffeae8, init=0x401222 <__libc_csu_init>,
    
42.     fini=0x40129a <__libc_csu_fini>, rtld_fini=0x7ffff7fd32b6 <_dl_fini>, stack_end=0x7fffffffead8)
    
43.     at ../csu/libc-start.c:366
    
44. 366          exit (result);
    
45. (gdb) l
    
46. 361        #else
    
47. 362          /* Nothing fancy, just call the function.  */
    
48. 363          result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
    
49. 364        #endif
    
50. 365       
    
51. 366          exit (result);
    
52. 367        }
    
53. (gdb) kill
    
54. Kill the program being debugged? (y or n) y
    
55. [Inferior 1 (process 854883) killed]
    
56. (gdb) b _start
    
57. Breakpoint 2 at 0x401090: file ../sysdeps/x86_64/start.S, line 63.
    
58. (gdb) r
    
59. Starting program: /tmp/main
    
60. warning: File "/usr/lib/libstdc++.so.6.0.29-gdb.py" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
    
61. 
    
62. Breakpoint 2, _start () at ../sysdeps/x86_64/start.S:63
    
63. 63                xorl %ebp, %ebp
    
64. (gdb) l
    
65. 58        ENTRY (_start)
    
66. 59                /* Clearing frame pointer is insufficient, use CFI.  */
    
67. 60                cfi_undefined (rip)
    
68. 61                /* Clear the frame pointer.  The ABI suggests this be done, to mark
    
69. 62                   the outermost frame obviously.  */
    
70. 63                xorl %ebp, %ebp
    
71. 64       
    
72. 65                /* Extract the arguments as encoded on the stack and set up
    
73. 66                   the arguments for __libc_start_main (int (*main) (int, char **, char **),
    
74. 67                           int argc, char *argv,
    
75. (gdb) n
    
76. 79                mov %RDX_LP, %R9_LP        /* Address of the shared library termination
    
77. (gdb)
    
78. 85                popq %rsi                /* Pop the argument count.  */
    
79. (gdb)
    
80. 88                mov %RSP_LP, %RDX_LP
    
81. (gdb)
    
82. 90                and  $~15, %RSP_LP
    
83. (gdb)
    
84. 93                pushq %rax
    
85. (gdb)
    
86. 97                pushq %rsp
    
87. (gdb)
    
88. 101                mov __libc_csu_fini@GOTPCREL(%rip), %R8_LP
    
89. (gdb)
    
90. 102                mov __libc_csu_init@GOTPCREL(%rip), %RCX_LP
    
91. (gdb)
    
92. 104                mov main@GOTPCREL(%rip), %RDI_LP
    
93. (gdb)
    
94. 120                call *__libc_start_main@GOTPCREL(%rip)
    
95. (gdb)
    
96. 
    
97. Breakpoint 1, main () at main.cpp:6
    
98. 6            cout << "hello world" << endl;
    
99. (gdb) kill
    
100. Kill the program being debugged? (y or n) y
     
101. [Inferior 1 (process 855406) killed]
     
102. (gdb) r
     
103. Starting program: /tmp/main
     
104. warning: File "/usr/lib/libstdc++.so.6.0.29-gdb.py" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
     
105. 
     
106. Breakpoint 2, _start () at ../sysdeps/x86_64/start.S:63
     
107. 63                xorl %ebp, %ebp
     
108. (gdb) n
     
109. 79                mov %RDX_LP, %R9_LP        /* Address of the shared library termination
     
110. (gdb)
     
111. 85                popq %rsi                /* Pop the argument count.  */
     
112. (gdb)
     
113. 88                mov %RSP_LP, %RDX_LP
     
114. (gdb)
     
115. 90                and  $~15, %RSP_LP
     
116. (gdb)
     
117. 93                pushq %rax
     
118. (gdb)
     
119. 97                pushq %rsp
     
120. (gdb)
     
121. 101                mov __libc_csu_fini@GOTPCREL(%rip), %R8_LP
     
122. (gdb)
     
123. 102                mov __libc_csu_init@GOTPCREL(%rip), %RCX_LP
     
124. (gdb)
     
125. 104                mov main@GOTPCREL(%rip), %RDI_LP
     
126. (gdb)
     
127. 120                call *__libc_start_main@GOTPCREL(%rip)
     
128. (gdb) s
     
129. __libc_start_main (main=0x4011a8 <main()>, argc=1, argv=0x7fffffffeae8, init=0x401222 <__libc_csu_init>,
     
130.     fini=0x40129a <__libc_csu_fini>, rtld_fini=0x7ffff7fd32b6 <_dl_fini>, stack_end=0x7fffffffead8)
     
131.     at ../csu/libc-start.c:248
     
132. 248          if (__glibc_likely (rtld_fini != NULL))
     
133. (gdb) n
     
134. 249            __cxa_atexit ((void (*) (void *)) rtld_fini, NULL, NULL);
     
135. (gdb)
     
136. 275          if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
     
137. (gdb)
     
138. 278          if (init)
     
139. (gdb)
     
140. 279            (*init) (argc, argv, __environ MAIN_AUXVEC_PARAM);
     
141. (gdb)
     
142. 283          if (__glibc_unlikely (GLRO(dl_naudit) > 0))
     
143. (gdb)
     
144. 298          if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS))
     
145. (gdb)
     
146. 318          not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
     
147. (gdb)
     
148. 320          if (__glibc_likely (! not_first_call))
     
149. (gdb)
     
150. 322              struct pthread *self = THREAD_SELF;
     
151. (gdb)
     
152. 325              unwind_buf.priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
     
153. (gdb)
     
154. 326              unwind_buf.priv.data.cleanup = THREAD_GETMEM (self, cleanup);
     
155. (gdb)
     
156. 329              THREAD_SETMEM (self, cleanup_jmp_buf, &unwind_buf);
     
157. (gdb)
     
158. 332              result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
     
159. (gdb) s
     
160. 
     
161. Breakpoint 1, main () at main.cpp:6
     
162. 6            cout << "hello world" << endl;
     
163. (gdb) n
     
164. hello world
     
165. 7            return 0;
     
166. (gdb)
     
167. 8        }
     
168. (gdb)
     
169. __libc_start_main (main=0x4011a8 <main()>, argc=1, argv=0x7fffffffeae8, init=0x401222 <__libc_csu_init>,
     
170.     fini=0x40129a <__libc_csu_fini>, rtld_fini=0x7ffff7fd32b6 <_dl_fini>, stack_end=0x7fffffffead8)
     
171.     at ../csu/libc-start.c:366
     
172. 366          exit (result);
     
173. (gdb) l
     
174. 361        #else
     
175. 362          /* Nothing fancy, just call the function.  */
     
176. 363          result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
     
177. 364        #endif
     
178. 365       
     
179. 366          exit (result);
     
180. 367        }
     
181. (gdb) n
     
182. [Inferior 1 (process 855505) exited normally]
     
183. (gdb)

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跳转到最佳答案楼层

人造人

你用的是单步步入指令 s 吧
这会在最后让程序停在调用 main 函数的下一条语句
main 函数是在 libc-start.c 文件中调用的，你用 s 指令就返回到这个文件了
一般 gcc 不提供这个文件，当然就找不到了
这不算是错误
你可以自己编译 gcc 的源代码，这个文件在 gcc 的源代码中
要在源代码级别调试库函数，你需要自己编译一个带源代码版本且不开优化的 gcc 编译器，当然还有依赖的库

1. # gdb main
   
2. GNU gdb (GDB) 10.2
   
3. Copyright (C) 2021 Free Software Foundation, Inc.
   
4. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
   
5. This is free software: you are free to change and redistribute it.
   
6. There is NO WARRANTY, to the extent permitted by law.
   
7. Type "show copying" and "show warranty" for details.
   
8. This GDB was configured as "x86_64-pc-linux-gnu".
   
9. Type "show configuration" for configuration details.
   
10. For bug reporting instructions, please see:
    
11. <https://www.gnu.org/software/gdb/bugs/>.
    
12. Find the GDB manual and other documentation resources online at:
    
13.     <http://www.gnu.org/software/gdb/documentation/>.
    
14. 
    
15. For help, type "help".
    
16. Type "apropos word" to search for commands related to "word"...
    
17. Reading symbols from main...
    
18. (gdb) b main
    
19. Breakpoint 1 at 0x4011ac: file main.cpp, line 6.
    
20. (gdb) r
    
21. Starting program: /tmp/main
    
22. warning: File "/usr/lib/libstdc++.so.6.0.29-gdb.py" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
    
23. To enable execution of this file add
    
24.         add-auto-load-safe-path /usr/lib/libstdc++.so.6.0.29-gdb.py
    
25. line to your configuration file "/root/.gdbinit".
    
26. To completely disable this security protection add
    
27.         set auto-load safe-path /
    
28. line to your configuration file "/root/.gdbinit".
    
29. For more information about this security protection see the
    
30. "Auto-loading safe path" section in the GDB manual.  E.g., run from the shell:
    
31.         info "(gdb)Auto-loading safe path"
    
32. 
    
33. Breakpoint 1, main () at main.cpp:6
    
34. 6            cout << "hello world" << endl;
    
35. (gdb) n
    
36. hello world
    
37. 7            return 0;
    
38. (gdb) s
    
39. 8        }
    
40. (gdb) s
    
41. __libc_start_main (main=0x4011a8 <main()>, argc=1, argv=0x7fffffffeae8, init=0x401222 <__libc_csu_init>,
    
42.     fini=0x40129a <__libc_csu_fini>, rtld_fini=0x7ffff7fd32b6 <_dl_fini>, stack_end=0x7fffffffead8)
    
43.     at ../csu/libc-start.c:366
    
44. 366          exit (result);
    
45. (gdb) l
    
46. 361        #else
    
47. 362          /* Nothing fancy, just call the function.  */
    
48. 363          result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
    
49. 364        #endif
    
50. 365       
    
51. 366          exit (result);
    
52. 367        }
    
53. (gdb)

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1. # gdb main
   
2. GNU gdb (GDB) 10.2
   
3. Copyright (C) 2021 Free Software Foundation, Inc.
   
4. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
   
5. This is free software: you are free to change and redistribute it.
   
6. There is NO WARRANTY, to the extent permitted by law.
   
7. Type "show copying" and "show warranty" for details.
   
8. This GDB was configured as "x86_64-pc-linux-gnu".
   
9. Type "show configuration" for configuration details.
   
10. For bug reporting instructions, please see:
    
11. <https://www.gnu.org/software/gdb/bugs/>.
    
12. Find the GDB manual and other documentation resources online at:
    
13.     <http://www.gnu.org/software/gdb/documentation/>.
    
14. 
    
15. For help, type "help".
    
16. Type "apropos word" to search for commands related to "word"...
    
17. Reading symbols from main...
    
18. (gdb) b main
    
19. Breakpoint 1 at 0x4011ac: file main.cpp, line 6.
    
20. (gdb) r
    
21. Starting program: /tmp/main
    
22. warning: File "/usr/lib/libstdc++.so.6.0.29-gdb.py" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
    
23. To enable execution of this file add
    
24.         add-auto-load-safe-path /usr/lib/libstdc++.so.6.0.29-gdb.py
    
25. line to your configuration file "/root/.gdbinit".
    
26. To completely disable this security protection add
    
27.         set auto-load safe-path /
    
28. line to your configuration file "/root/.gdbinit".
    
29. For more information about this security protection see the
    
30. "Auto-loading safe path" section in the GDB manual.  E.g., run from the shell:
    
31.         info "(gdb)Auto-loading safe path"
    
32. 
    
33. Breakpoint 1, main () at main.cpp:6
    
34. 6            cout << "hello world" << endl;
    
35. (gdb) n
    
36. hello world
    
37. 7            return 0;
    
38. (gdb) s
    
39. 8        }
    
40. (gdb) s
    
41. __libc_start_main (main=0x4011a8 <main()>, argc=1, argv=0x7fffffffeae8, init=0x401222 <__libc_csu_init>,
    
42.     fini=0x40129a <__libc_csu_fini>, rtld_fini=0x7ffff7fd32b6 <_dl_fini>, stack_end=0x7fffffffead8)
    
43.     at ../csu/libc-start.c:366
    
44. 366          exit (result);
    
45. (gdb) l
    
46. 361        #else
    
47. 362          /* Nothing fancy, just call the function.  */
    
48. 363          result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
    
49. 364        #endif
    
50. 365       
    
51. 366          exit (result);
    
52. 367        }
    
53. (gdb) kill
    
54. Kill the program being debugged? (y or n) y
    
55. [Inferior 1 (process 854883) killed]
    
56. (gdb) b _start
    
57. Breakpoint 2 at 0x401090: file ../sysdeps/x86_64/start.S, line 63.
    
58. (gdb) r
    
59. Starting program: /tmp/main
    
60. warning: File "/usr/lib/libstdc++.so.6.0.29-gdb.py" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
    
61. 
    
62. Breakpoint 2, _start () at ../sysdeps/x86_64/start.S:63
    
63. 63                xorl %ebp, %ebp
    
64. (gdb) l
    
65. 58        ENTRY (_start)
    
66. 59                /* Clearing frame pointer is insufficient, use CFI.  */
    
67. 60                cfi_undefined (rip)
    
68. 61                /* Clear the frame pointer.  The ABI suggests this be done, to mark
    
69. 62                   the outermost frame obviously.  */
    
70. 63                xorl %ebp, %ebp
    
71. 64       
    
72. 65                /* Extract the arguments as encoded on the stack and set up
    
73. 66                   the arguments for __libc_start_main (int (*main) (int, char **, char **),
    
74. 67                           int argc, char *argv,
    
75. (gdb) n
    
76. 79                mov %RDX_LP, %R9_LP        /* Address of the shared library termination
    
77. (gdb)
    
78. 85                popq %rsi                /* Pop the argument count.  */
    
79. (gdb)
    
80. 88                mov %RSP_LP, %RDX_LP
    
81. (gdb)
    
82. 90                and  $~15, %RSP_LP
    
83. (gdb)
    
84. 93                pushq %rax
    
85. (gdb)
    
86. 97                pushq %rsp
    
87. (gdb)
    
88. 101                mov __libc_csu_fini@GOTPCREL(%rip), %R8_LP
    
89. (gdb)
    
90. 102                mov __libc_csu_init@GOTPCREL(%rip), %RCX_LP
    
91. (gdb)
    
92. 104                mov main@GOTPCREL(%rip), %RDI_LP
    
93. (gdb)
    
94. 120                call *__libc_start_main@GOTPCREL(%rip)
    
95. (gdb)
    
96. 
    
97. Breakpoint 1, main () at main.cpp:6
    
98. 6            cout << "hello world" << endl;
    
99. (gdb) kill
    
100. Kill the program being debugged? (y or n) y
     
101. [Inferior 1 (process 855406) killed]
     
102. (gdb) r
     
103. Starting program: /tmp/main
     
104. warning: File "/usr/lib/libstdc++.so.6.0.29-gdb.py" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
     
105. 
     
106. Breakpoint 2, _start () at ../sysdeps/x86_64/start.S:63
     
107. 63                xorl %ebp, %ebp
     
108. (gdb) n
     
109. 79                mov %RDX_LP, %R9_LP        /* Address of the shared library termination
     
110. (gdb)
     
111. 85                popq %rsi                /* Pop the argument count.  */
     
112. (gdb)
     
113. 88                mov %RSP_LP, %RDX_LP
     
114. (gdb)
     
115. 90                and  $~15, %RSP_LP
     
116. (gdb)
     
117. 93                pushq %rax
     
118. (gdb)
     
119. 97                pushq %rsp
     
120. (gdb)
     
121. 101                mov __libc_csu_fini@GOTPCREL(%rip), %R8_LP
     
122. (gdb)
     
123. 102                mov __libc_csu_init@GOTPCREL(%rip), %RCX_LP
     
124. (gdb)
     
125. 104                mov main@GOTPCREL(%rip), %RDI_LP
     
126. (gdb)
     
127. 120                call *__libc_start_main@GOTPCREL(%rip)
     
128. (gdb) s
     
129. __libc_start_main (main=0x4011a8 <main()>, argc=1, argv=0x7fffffffeae8, init=0x401222 <__libc_csu_init>,
     
130.     fini=0x40129a <__libc_csu_fini>, rtld_fini=0x7ffff7fd32b6 <_dl_fini>, stack_end=0x7fffffffead8)
     
131.     at ../csu/libc-start.c:248
     
132. 248          if (__glibc_likely (rtld_fini != NULL))
     
133. (gdb) n
     
134. 249            __cxa_atexit ((void (*) (void *)) rtld_fini, NULL, NULL);
     
135. (gdb)
     
136. 275          if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
     
137. (gdb)
     
138. 278          if (init)
     
139. (gdb)
     
140. 279            (*init) (argc, argv, __environ MAIN_AUXVEC_PARAM);
     
141. (gdb)
     
142. 283          if (__glibc_unlikely (GLRO(dl_naudit) > 0))
     
143. (gdb)
     
144. 298          if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS))
     
145. (gdb)
     
146. 318          not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
     
147. (gdb)
     
148. 320          if (__glibc_likely (! not_first_call))
     
149. (gdb)
     
150. 322              struct pthread *self = THREAD_SELF;
     
151. (gdb)
     
152. 325              unwind_buf.priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
     
153. (gdb)
     
154. 326              unwind_buf.priv.data.cleanup = THREAD_GETMEM (self, cleanup);
     
155. (gdb)
     
156. 329              THREAD_SETMEM (self, cleanup_jmp_buf, &unwind_buf);
     
157. (gdb)
     
158. 332              result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
     
159. (gdb) s
     
160. 
     
161. Breakpoint 1, main () at main.cpp:6
     
162. 6            cout << "hello world" << endl;
     
163. (gdb) n
     
164. hello world
     
165. 7            return 0;
     
166. (gdb)
     
167. 8        }
     
168. (gdb)
     
169. __libc_start_main (main=0x4011a8 <main()>, argc=1, argv=0x7fffffffeae8, init=0x401222 <__libc_csu_init>,
     
170.     fini=0x40129a <__libc_csu_fini>, rtld_fini=0x7ffff7fd32b6 <_dl_fini>, stack_end=0x7fffffffead8)
     
171.     at ../csu/libc-start.c:366
     
172. 366          exit (result);
     
173. (gdb) l
     
174. 361        #else
     
175. 362          /* Nothing fancy, just call the function.  */
     
176. 363          result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
     
177. 364        #endif
     
178. 365       
     
179. 366          exit (result);
     
180. 367        }
     
181. (gdb) n
     
182. [Inferior 1 (process 855505) exited normally]
     
183. (gdb)

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