GDB 1 GDB 2 GDB. Fortran Pascal GDB 4. hoge.c. Fig. 1. calc.c. Fig GDB. GDB Debian. # apt-get install gdb

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1 2003 advanced seminar Intelligent Systems Design Lab. 1 GDB : GDB GDB GDB 1 GDB GDB ( ) Free Software Foundation(FSF) GDB 5.3 C,C++ 1 Fortran Pascal GDB 4 GDB 2 GDB Fig. 1 hoge.c calc.c GDB Fig. 2 hoge.c #include <stdio.h> #include "calc.h" int main() { int a = 12; int answer; int i; calc.c #include "calc.h" int calc(int x, int y){ int ans; ans = x / y; return ans; } printf(" \n\n"); for(i=3; i>=0; i--){ printf("a = %d,\ti = %d\n",a,i); answer = calc(a,i); printf("%d / %d = %d\n",a,i,answer); } return 0; } Fig GDB GDB Debian # apt-get install gdb 1 Java jdb Java jdb Java JDK JDK GDB 1

2 $./run_hoge a = 12, i = 3 12 / 3 = 4 a = 12, i = 2 12 / 2 = 6 a = 12, i = 1 12 / 1 = 12 a = 12, i = 0 Floating point exception (core dumped) Fig GDB -g $ gcc hoge.c calc.c -g -o run_hoge 2.3 GDB GDB run hoge GDB GDB $ gdb run_hoge [ messeage...] 2.4 run 2.5 cont 2.6 quit GDB 3 GDB GDB 3.1 GDB 1 2

3 break break break : or C++ break : ( ) Fig. 3 break main run calc.c calc cont break main Breakpoint 1 at 0x80483f6: file hoge.c, line 6. run Breakpoint 1, main () at hoge.c:6 6 int a = 12; break calc Breakpoint 2 at 0x : file calc.c, line 5. cont a = 12, i = 3 Breakpoint 2, calc (x=12, y=3) at calc.c:5 cont 12 / 1 = 12 a = 12, i = 0 Breakpoint 2, calc (x=12, y=0) at calc.c:5 cont Program received signal SIGFPE, Arithmetic exception. 0x d in calc (x=12, y=0) at calc.c:5 Fig. 3 GDB 3

4 info break Num Type Disp Enb Address What 1 breakpoint keep y 0x080483f6 in main at hoge.c:6 breakpoint already hit 1 time 2 breakpoint keep y 0x in calc at calc.c:5 breakpoint already hit 4 times info break delete 1 info break Num Type Disp Enb Address What 2 breakpoint keep y 0x in calc at calc.c:5 breakpoint already hit 4 times delete 3.2 list list list 10 list 1 #include <stdio.h> 2 #include "calc.h" 3 4 int main() 5 { 6 int a = 12; 7 int answer; 8 int i; 9 10 printf(" \n\n"); 11 for(i=3; i>=0; i--){ 12 printf("a = %d,\ti = %d\n",a,i); 14 printf("%d / %d = %d\n",a,i,answer); 15 printf("\n"); 16 } 17 return 0; 18 } Line number 19 out of range; hoge.c has 18 lines. Fig. 4 list gdb 1 4

5 list calc 1 #include "calc.h" 2 3 int calc(int x, int y){ 4 int ans; 6 return ans; 7 } Line number 8 out of range; calc.c has 7 lines. Fig. 5 list calc 3.3 print print print 2 break 12 Breakpoint 1 at 0x : file hoge.c, line 12. run Starting program: /home/yoneda/gdb/gdb_program/run_hoge Breakpoint 1, main () at hoge.c:12 12 printf("a = %d,\ti = %d\n",a,i); print a $1 = 12 print i $2 = 3 Fig. 6 print print Fig. 7 Fig. 8 1 #include<stdio.h> 2 3 int main(){ 4 int i; 5 int a[10]; 6 7 for(i=0;i<10;i++){ 8 a[i]=i; 9 fprintf(stderr,"a[%d] = %d\n",i,a[i]); 10 } 11 return 0; 12 } Fig. 7 Fig next step next step next step next step next 5

6 break 9 Breakpoint 1 at 0x804849f: file test.c, line 9. run Starting program: /home/yoneda/gdb/hoge/test1_run Breakpoint 1, main () at test.c:9 9 fprintf(stderr,"a[%d] = %d\n",i,a[i]); print a $1 = {0, , 1, , , , , , , } print a $2 = {0, 1, 2, 3, 4, 5, , , , } print a $3 = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} Fig. 8 print step hoge.c 1 #include <stdio.h> 2 #include "calc.h" 3 4 int main() 5 { 6 int a = 12; 7 int answer; 8 int i; 9 10 printf(" \n\n"); 11 for(i=3; i>=0; i--){ 12 printf("a = %d,\ti = %d\n",a,i); 14 printf("%d / %d = %d\n",a,i,answer); 15 printf("\n"); 16 } 17 return 0; 18 } calc.c 1 #include "calc.h" 2 3 int calc(int x, int y){ 4 int ans; 6 return ans; 7 } Fig. 9 Fig. 10 Fig. 11 step calc next calc next step 6

7 break 13 Breakpoint 1 at 0x : file hoge.c, line 13. run Starting program: /home/yoneda/gdb/gdb_program/run_hoge a = 12, i = 3 Breakpoint 1, main () at hoge.c:13 next 14 printf("%d / %d = %d\n",a,i,answer); 12 / 3 = 4 15 printf("\n"); cont a = 12, i = 2 Breakpoint 1, main () at hoge.c:13 Fig. 10 gdb) break 13 Breakpoint 1 at 0x : file hoge.c, line 13. run Starting program: /home/yoneda/gdb/gdb_program/run_hoge next a = 12, i = 3 Breakpoint 1, main () at hoge.c:13 step calc (x=12, y=3) at calc.c:5 6 return ans; 7 } main () at hoge.c:14 14 printf("%d / %d = %d\n",a,i,answer); cont 12 / 3 = 4 a = 12, i = 2 Breakpoint 1, main () at hoge.c:13 Fig. 11 step 3.5 help Fig. 12 help Fig. 12 help Fig. 12 help break bre b 7

8 step stepi s step next step help List of classes of commands: aliases -- Aliases of other commands breakpoints -- Making program stop at certain points data -- Examining data files -- Specifying and examining files internals -- Maintenance commands obscure -- Obscure features running -- Running the program < > Type "help" followed by a class name for a list of commands in that class. Type "help" followed by command name for full documentation. Command name abbreviations are allowed if unambiguous. help running Running the program. List of commands: attach -- Attach to a process or file outside of GDB continue -- Continue program being debugged detach -- Detach a process or file previously attached finish -- Execute until selected stack frame returns < > Type "help" followed by command name for full documentation. Command name abbreviations are allowed if unambiguous. help run Start debugged program. You may specify arguments to give it. Args may include "*", or "[...]"; they are expanded using "sh". Input and output redirection with ">", "<", or ">>" are also allowed. With no arguments, uses arguments last specified (with "run" or "set args"). To cancel previous arguments and run with no arguments, use "set args" without arguments. Fig. 12 help 8