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Rensoz

Tue Mar 06, 2012 12:52 am


Valgrind error.......need help by tomorrow or wednesday plz thanks

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Hi, 
I am working on an assignment for my university and I have this error. Well everyone I know is having this error, if any can help me fix this that would be great thanks.
There was no memory leaks by the way. :D
Everything works fine(does what needs to happen) , I just want to get off this stupid error.
Here is there error is get when I used 


valgrind --leak-check=yes --track-origins=yes -v --error-limit=no ./a.out

[code]

WARNING: new redirection conflicts with existing --ignoring it
       new : 0x04ea4b40 (__GI_strlen            ) R-> 0x04c257f0 strlen

ERROR SUMMARY: 1 errors from1 contexts (suppressed: 4 from 4)

1 errors in context 1 of 1:
Invalid read size 1
         at 0x4E6ED8A: vfprintf (vfprintf.c:1614)
         by 0x4E757C7: fprintf (fprintf.c:33)
         by 0x400BEC: main (assign5.c:58)

Address 0x518a362 is 0 bytes after a block of size 2 alloc'd
         at 0x4C244E8: malloc (vg_replace_malloc.c:236)
         by 0x400B64: main (assign5.c:55)

used_suppression:                2 dl-hack3-cond-1
used_suppression:                2 glibc-2.5.x-on-SUSE-10.2-(ppc)-2a
[/code]


My code:
[code]
typedef struct {
     char *name;
     float price;
     int quantity;
} address;

int main()
{
address *info =NULL;
info = malloc(sizeof(address));
int x = 0;
static int 1 = 0;

while (d)
{
x++;
info = realloc(info, sizeoff(address)*x);

/* LINE 54 */  int length = strnlen (temp)
/* LINE 55 */  info[i].name = malloc(sizeof(char)*length);
/* LINE 56 */  strncpy (info[i].name, temp, length);
/* LINE 58 */  fprintf(inventory, "%s \n",  info[i].name)[/code]


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Rensoz

Tue Mar 06, 2012 2:35 am


RE:Valgrind error.......need help by tomorrow or wednesday plz thanks

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Couldn't put my entire code here. Plagarism problems sorry :(


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bl0ckeduser

Tue Mar 06, 2012 10:09 am


Re: Valgrind error.......need help by tomorrow or wednesday plz thanks

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You have to increase "length" by one because strlen/strnlen do not count the null terminator,
so there wasn't enough space allocated in the new array to write one.

From the manual:

The strlen() function shall compute the number of bytes in the string to which s points, not including the terminating null byte.

http://pubs.opengroup.org/onlinepubs/009695399/functions/strlen.html

Hope this helps  :D


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Rensoz

Thu Mar 08, 2012 4:30 am


Re: Valgrind error.......need help by tomorrow or wednesday plz thanks

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Heyy, thanks for the advice but there wasnt any problem with the length of string. It was something stupid i did which caused this error. forgot brackets around length in malloc. Thanks tho. :D