/* Неинициализированное чтение */
ch = ptr[1024];
/* Запись за пределами блока */
ptr[1024] = 0;
/* Потеря блока */
ptr = 0;
exit(0);
}
Для применения valgrind вы просто выполняете команду valgrind, передав ей опции, задающие нужные виды проверок, и далее указав программу для выполнения с ее аргументами (если таковые есть).
При выполнении программы с valgrind вы увидите множество обнаруженных проблем:
$ valgrind --leak-check=yes -v ./checker
==4780== Memcheck, a memory error detector.
==4780== Copyright (C) 2002-2007, and GNU GPL'd, by Julian Seward et al.
==4780== Using LibVEX rev 1732, a library for dynamic binary translation.
==4780== Copyright (C) 2004-2007, and GNU GPL'd, by OpenWorks LLP.
==4780== Using valgrind-3.2.3, a dynamic binary instrumentation framework.
==4780== Copyright (C) 2000-2007, and GNU GPL'd, by Julian Seward et al.
==4780==
--4780-- Command line
--4780-- ./checker
--4780-- Startup, with flags:
--4780-- --leak-check=yes
--4780-- -v
--4780-- Contents of /рroc/version:
--4780-- Linux version 2-6.20.2-2-default (geeko@buildhost) (gcc version 4.1.3 20070218 (prerelease) (SUSE Linux)) #1 SMP Fri Mar 9 21:54:10 UTC 2007
--4780-- Arch and hwcaps: X86, x86-sse1-sse2
--4780-- Page sizes: currently 4096, max supported 4096
--4780-- Valgrind library directory: /usr/lib/valgrind
--4780-- Reading syms from /lib/ld-2.5.so (0x4000000)
--4780-- Reading syms from /home/neil/BLP4e/chapter10/checker (0x8048000)
--4780-- Reading syms from /usr/lib/valgrind/x86-linux/memcheck (0x38000000)
--4780-- object doesn't have a symbol table
--4780-- object doesn't have a dynamic symbol table
--4780-- Reading suppressions file: /usr/lib/valgrind/default.supp
--4780-- REDIR: 0x40158B0 (index) redirected to 0x38027EDB (???)
--4780-- Reading syms from /usr/lib/valgrind/x86-linux/vgpreload_core.so (0x401E000)
--4780-- object doesn't have a symbol table
--4780-- Reading syms from /usr/lib/valgrind/x86-linux/vgpreload_memcheck.so (0x4021000)
--4780-- object doesn't have a symbol table
==4780= WARNING: new redirection conflicts with existing -- ignoring it
--4780-- new: 0x040158B0 (index ) R-> 0x04024490 index
--4780-- REDIR: 0x4015A50 (strlen) redirected to 0x4024540 (strlen)
--4780-- Reading syms from /lib/libc-2.5.so (0x4043000)
--4780-- REDIR: 0x40ADFF0 (rindex) redirected to 0x4024370 (rindex)
--4780-- REDIR: 0x40AAF00 (malloc) redirected to 0x4023700 (malloc)
==4780== Invalid read of size 1
==4780== at 0x804842C: main (checker.с: 10)
==4780== Address 0x4170428 is 0 bytes after a block of size 1,024 alloc'd
==4780== at 0x4023785: malloc (in /usr/lib/valgrind/x86-linux/vgpreload_memcheck.so)
