Ray Hurst wrote:
I'm running under Windows XP and Cygwin.
I ran GDB on a simple C program and captured the output (below).
I have a few questions:
Why can I run the program several times with no errors but as soon as I
set a breakpoint at main it gets a SIGSEGV fault?
Why does the backtrace show only addresses?
C:\Documents and Settings\Ray
Hurst\workspace\CDT\HelloWorld-ANSIC\Debug>gdb Hel
loWorld-ANSIC.exe
GNU gdb 6.5.50.20060706-cvs (cygwin-special)
Copyright (C) 2006 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you
are
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conditions.
Type "show copying" to see the conditions.
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This GDB was configured as "i686-pc-cygwin"...
(gdb) list
5 Version :
6 Copyright : Your copyright notice
7 Description : Hello World in C, Ansi-style
8 =======================================================================
=====
9 */
10
11 #include <stdio.h>
12 #include <stdlib.h>
13
14 int main(void) {
(gdb) list 20
15 puts("!!!Hello World!!!"); /* prints !!!Hello World!!! */
16 return EXIT_SUCCESS;
17 }
(gdb) run
Starting program: /cygdrive/c/Documents and Settings/Ray
Hurst/workspace/CDT/Hel
loWorld-ANSIC/Debug/HelloWorld-ANSIC.exe
Loaded symbols for /cygdrive/c/WINDOWS/system32/ntdll.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/kernel32.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/cygwin1.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/advapi32.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/rpcrt4.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/secur32.dll
!!!Hello World!!!
Program exited normally.
(gdb) run
Starting program: /cygdrive/c/Documents and Settings/Ray
Hurst/workspace/CDT/Hel
loWorld-ANSIC/Debug/HelloWorld-ANSIC.exe
Loaded symbols for /cygdrive/c/WINDOWS/system32/ntdll.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/kernel32.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/cygwin1.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/advapi32.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/rpcrt4.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/secur32.dll
!!!Hello World!!!
Program exited normally.
(gdb) b main
Breakpoint 1 at 0x401050: file ../src/HelloWorld-ANSIC.c, line 14.
(gdb) run
Starting program: /cygdrive/c/Documents and Settings/Ray
Hurst/workspace/CDT/Hel
loWorld-ANSIC/Debug/HelloWorld-ANSIC.exe
Loaded symbols for /cygdrive/c/WINDOWS/system32/ntdll.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/kernel32.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/cygwin1.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/advapi32.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/rpcrt4.dll
Loaded symbols for /cygdrive/c/WINDOWS/system32/secur32.dll
Program received signal SIGSEGV, Segmentation fault.
[Switching to thread 4896.0x1314]
0x000007f4 in ?? ()
(gdb) bt
#0 0x000007f4 in ?? ()
#1 0x00000000 in ?? ()
(gdb)
Ray
Works fine on my Windows XP Pro machine using the same GDB and gcc
version 3.4.4. What gcc version do you have?
The stack trace would indicate that the crash is occurring before it
gets to your main function, since that code doesn't have debug symbols
you get addresses.
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