The Linux Development Platform Configuring, Using, and ... - Classes
The Linux Development Platform Configuring, Using, and ... - Classes
The Linux Development Platform Configuring, Using, and ... - Classes
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CH05.fm Page 166 Monday, October 7, 2002 9:00 PM<br />
166 Chapter 5 • Working with GNU Debugger<br />
this point <strong>and</strong> start gdb in the new window to attach the process. <strong>The</strong> following comm<strong>and</strong> starts<br />
the process which is waiting for the user to enter the first number.<br />
[rr@conformix 5]$ ./sumf<br />
Enter first number :<br />
Open a new terminal window <strong>and</strong> find out the process ID of the sumf process. This can<br />
be easily done using the ps comm<strong>and</strong> as follows:<br />
[rr@conformix 5]$ ps –a|grep sumf<br />
4272 pts/4 00:00:00 sumf<br />
[rr@conformix 5]$<br />
<strong>The</strong> process ID for the running process is 4272. After getting this information, you can<br />
start gdb <strong>and</strong> load the sumf file that contains the symbol table. This is done using the file<br />
comm<strong>and</strong>. <strong>The</strong> following sequence of comm<strong>and</strong>s shows this process:<br />
[rr@conformix 5]$ gdb<br />
GNU gdb 5.0rh-5 Red Hat <strong>Linux</strong> 7.1<br />
Copyright 2001 Free Software Foundation, Inc.<br />
GDB is free software, covered by the GNU General Public<br />
License, <strong>and</strong> you are<br />
welcome to change it <strong>and</strong>/or distribute copies of it under<br />
certain conditions.<br />
Type "show copying" to see the conditions.<br />
<strong>The</strong>re is absolutely no warranty for GDB. Type "show warranty"<br />
for details.<br />
This GDB was configured as "i386-redhat-linux".<br />
(gdb) file sumf<br />
Reading symbols from sumf...done.<br />
(gdb)<br />
Now you can attach to the program with ID 4272. Note that the program is waiting for<br />
user input <strong>and</strong> there are many functions calls from loaded shared libraries. To come back to this<br />
point in the main source file, you have to make a number of finish comm<strong>and</strong>s.<br />
(gdb) attach 4272<br />
Attaching to program: /home/rr/5/sumf, process 4272<br />
Reading symbols from /lib/i686/libc.so.6...done.<br />
Loaded symbols for /lib/i686/libc.so.6<br />
Reading symbols from /lib/ld-linux.so.2...done.<br />
Loaded symbols for /lib/ld-linux.so.2<br />
0x40105f44 in __libc_read () from /lib/i686/libc.so.6<br />
(gdb) n<br />
Single stepping until exit from function __libc_read,<br />
which has no line number information.<br />
_IO_file_read (fp=0x401548e0, buf=0x40019000, size=1024) at<br />
fileops.c:764<br />
764 fileops.c: No such file or directory.<br />
in fileops.c
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