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reagent/01_stack_allocation.c

Created September 18, 2012 17:21
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01_stack_allocation.c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
struct Person {
char *name;
};
struct Person *create_person_stack(char *name)
{
struct Person person;
person.name = name;
struct Person *person_ptr = &person;
return person_ptr;
}
struct Person *create_person_heap(char *name)
{
struct Person *person_ptr = malloc(sizeof(struct Person));
person_ptr->name = name;
return person_ptr;
}
int main(int argc, char *argv[])
{
struct Person *person_1 = create_person_stack("Patrick");
struct Person *person_2 = create_person_heap("Patrick");
printf("Person 1's name is %s.\n", person_1->name);
printf("Person 2's name is %s.\n", person_2->name);
return 0;
}
Raw
02_valgrind.txt
==22497== Memcheck, a memory error detector
==22497== Copyright (C) 2002-2010, and GNU GPL'd, by Julian Seward et al.
==22497== Using Valgrind-3.6.1 and LibVEX; rerun with -h for copyright info
==22497== Command: ./stack_allocation
==22497==
==22497== Use of uninitialised value of size 8
==22497== at 0x1000134F6: strlen (mc_replace_strmem.c:282)
==22497== by 0x100034B1B: __vfprintf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100075DCA: vfprintf_l (in /usr/lib/libSystem.B.dylib)
==22497== by 0x1000A3482: printf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100000E67: main (stack_allocation.c:32)
==22497==
==22497== Use of uninitialised value of size 8
==22497== at 0x100013503: strlen (mc_replace_strmem.c:282)
==22497== by 0x100034B1B: __vfprintf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100075DCA: vfprintf_l (in /usr/lib/libSystem.B.dylib)
==22497== by 0x1000A3482: printf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100000E67: main (stack_allocation.c:32)
==22497==
==22497== Use of uninitialised value of size 8
==22497== at 0x10001361C: memchr (mc_replace_strmem.c:558)
==22497== by 0x100038306: __sfvwrite (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100037CFB: __vfprintf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100075DCA: vfprintf_l (in /usr/lib/libSystem.B.dylib)
==22497== by 0x1000A3482: printf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100000E67: main (stack_allocation.c:32)
==22497==
==22497== Use of uninitialised value of size 8
==22497== at 0x100013634: memchr (mc_replace_strmem.c:558)
==22497== by 0x100038306: __sfvwrite (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100037CFB: __vfprintf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100075DCA: vfprintf_l (in /usr/lib/libSystem.B.dylib)
==22497== by 0x1000A3482: printf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100000E67: main (stack_allocation.c:32)
==22497==
==22497== Conditional jump or move depends on uninitialised value(s)
==22497== at 0x100014A6F: memcpy (mc_replace_strmem.c:77)
==22497== by 0x100038394: __sfvwrite (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100037CFB: __vfprintf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100075DCA: vfprintf_l (in /usr/lib/libSystem.B.dylib)
==22497== by 0x1000A3482: printf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100000E67: main (stack_allocation.c:32)
==22497==
==22497== Conditional jump or move depends on uninitialised value(s)
==22497== at 0x100014A85: memcpy (mc_replace_strmem.c:635)
==22497== by 0x100038394: __sfvwrite (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100037CFB: __vfprintf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100075DCA: vfprintf_l (in /usr/lib/libSystem.B.dylib)
==22497== by 0x1000A3482: printf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100000E67: main (stack_allocation.c:32)
==22497==
==22497== Conditional jump or move depends on uninitialised value(s)
==22497== at 0x100014A93: memcpy (mc_replace_strmem.c:635)
==22497== by 0x100038394: __sfvwrite (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100037CFB: __vfprintf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100075DCA: vfprintf_l (in /usr/lib/libSystem.B.dylib)
==22497== by 0x1000A3482: printf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100000E67: main (stack_allocation.c:32)
==22497==
==22497== Conditional jump or move depends on uninitialised value(s)
==22497== at 0x100014AE0: memcpy (mc_replace_strmem.c:635)
==22497== by 0x100038394: __sfvwrite (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100037CFB: __vfprintf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100075DCA: vfprintf_l (in /usr/lib/libSystem.B.dylib)
==22497== by 0x1000A3482: printf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100000E67: main (stack_allocation.c:32)
==22497==
==22497== Conditional jump or move depends on uninitialised value(s)
==22497== at 0x100014AF5: memcpy (mc_replace_strmem.c:635)
==22497== by 0x100038394: __sfvwrite (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100037CFB: __vfprintf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100075DCA: vfprintf_l (in /usr/lib/libSystem.B.dylib)
==22497== by 0x1000A3482: printf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100000E67: main (stack_allocation.c:32)
==22497==
==22497== Conditional jump or move depends on uninitialised value(s)
==22497== at 0x100014BD9: memcpy (mc_replace_strmem.c:635)
==22497== by 0x100038394: __sfvwrite (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100037CFB: __vfprintf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100075DCA: vfprintf_l (in /usr/lib/libSystem.B.dylib)
==22497== by 0x1000A3482: printf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100000E67: main (stack_allocation.c:32)
==22497==
==22497== Use of uninitialised value of size 8
==22497== at 0x100014BF0: memcpy (mc_replace_strmem.c:635)
==22497== by 0x100038394: __sfvwrite (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100037CFB: __vfprintf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100075DCA: vfprintf_l (in /usr/lib/libSystem.B.dylib)
==22497== by 0x1000A3482: printf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100000E67: main (stack_allocation.c:32)
==22497==
==22497== Use of uninitialised value of size 8
==22497== at 0x100014C01: memcpy (mc_replace_strmem.c:635)
==22497== by 0x100038394: __sfvwrite (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100037CFB: __vfprintf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100075DCA: vfprintf_l (in /usr/lib/libSystem.B.dylib)
==22497== by 0x1000A3482: printf (in /usr/lib/libSystem.B.dylib)
==22497== by 0x100000E67: main (stack_allocation.c:32)
==22497==
Person 1's name is Patrick.
Person 2's name is Patrick.
==22497==
==22497== HEAP SUMMARY:
==22497== in use at exit: 4,192 bytes in 3 blocks
==22497== total heap usage: 3 allocs, 0 frees, 4,192 bytes allocated
==22497==
==22497== LEAK SUMMARY:
==22497== definitely lost: 8 bytes in 1 blocks
==22497== indirectly lost: 0 bytes in 0 blocks
==22497== possibly lost: 0 bytes in 0 blocks
==22497== still reachable: 4,184 bytes in 2 blocks
==22497== suppressed: 0 bytes in 0 blocks
==22497== Rerun with --leak-check=full to see details of leaked memory
==22497==
==22497== For counts of detected and suppressed errors, rerun with: -v
==22497== Use --track-origins=yes to see where uninitialised values come from
==22497== ERROR SUMMARY: 28 errors from 12 contexts (suppressed: 0 from 0)
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