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I have a function like below.The program has compiled without any errors
..But when I run it I am getting Error like this --->fibBigNumbers(186
malloc: *** error for object 0x100000ee2: pointer being freed was not
allocated
*** set a breakpoint in malloc_error_break to debug
021Abort trap.

Program:
void fibonacci(void)
{
static char* i = "1";
static char* j = "1";

char* fib = addBigNumbers(i,j);
printf("\n%s",fib);

char* temp = i;
i=j;
j=fib;
if (!strcmp(temp,"1"))
{
free(temp);
temp = NULL;
}
}

Please Help.
Thanks in Advance.

On 9/9/2012 9:14 AM, vaysagekv wrote:
> I have a function like below.The program has compiled without any errors
> .But when I run it I am getting Error like this --->fibBigNumbers(186
> malloc: *** error for object 0x100000ee2: pointer being freed was not
> allocated
> *** set a breakpoint in malloc_error_break to debug
> 021Abort trap.
>
> Program:
> void fibonacci(void)
> {
> static char* i = "1";
> static char* j = "1";
>
> char* fib = addBigNumbers(i,j);
> printf("\n%s",fib);
>
> char* temp = i;
> i=j;
> j=fib;
> if (!strcmp(temp,"1"))
> {
> free(temp);
> temp = NULL;
> }
> }

You must not free() memory you did not obtain from malloc()
(or calloc() or realloc()). When your code executes free(temp),
`temp' points to the "1" that initialized `i'. The memory
holding that string was not obtained from malloc(), so you must
not try to free() it.

Aside: It is possible that the !strcmp(temp,"1") test is
confusing you. You may have intended to call free() only when
`temp' points to something other than "1", but the actual code
does exactly the opposite: If `temp' points to something equal
to "1", strcmp(temp,"1") returns zero to say that the strings
are equal. Then the `!' converts that zero to one, which is
"true" for the `if' test. A hasty reading of `if(!strcmp(...))'
seems to say "Do something if the strings are not equal," but
in fact it says "Do something if the strings *are* equal." For
this reason (among others), I suggest you stop using the `!strcmp'
form and write `if(strcmp(...) == 0)' or `if(strcmp(...) != 0)'
to make your intent clearer.

--
Eric Sosman
d
"The speed at which the system fails is usually not important."

On 09/09/12 7:02 PM, pete wrote:
> vaysagekv wrote:
>>
>> I have a function like below.The program has compiled without any errors
>> .But when I run it I am getting Error like this --->fibBigNumbers(186
>> malloc: *** error for object 0x100000ee2: pointer being freed was not
>> allocated
>> *** set a breakpoint in malloc_error_break to debug
>> 021Abort trap.
>
>> static char* i = "1";
>> char* temp = i;
>> free(temp);
>
> The argument in a call to free(),
> should be a value which has previously been returned
> by either malloc or calloc or realloc.
> free() can also take a null pointer as an argument.
>
Hi,
Thanks for the reply .Here the argument I have given to free is
allocated by malloc in addBigNumbers function as below.
char* addBigNumbers(char* first,char* second)
{
short lenOfFirst = strlen(first);
short lenOfSecond = strlen(second);
short len = lenOfFirst >= lenOfSecond ? lenOfFirst : lenOfSecond;


char* result= malloc(len + 2);
short resultLen = len + 1;
if (result == NULL) {
printf("Error");
}
result[resultLen] = '\0';

.....
.....
.....

return result;

}
Thanks
vaysage

On 09/09/12 7:09 PM, Eric Sosman wrote:
> On 9/9/2012 9:14 AM, vaysagekv wrote:
>> I have a function like below.The program has compiled without any errors
>> .But when I run it I am getting Error like this --->fibBigNumbers(186
>> malloc: *** error for object 0x100000ee2: pointer being freed was not
>> allocated
>> *** set a breakpoint in malloc_error_break to debug
>> 021Abort trap.
>>
>> Program:
>> void fibonacci(void)
>> {
>> static char* i = "1";
>> static char* j = "1";
>>
>> char* fib = addBigNumbers(i,j);
>> printf("\n%s",fib);
>>
>> char* temp = i;
>> i=j;
>> j=fib;
>> if (!strcmp(temp,"1"))
>> {
>> free(temp);
>> temp = NULL;
>> }
>> }
>
> You must not free() memory you did not obtain from malloc()
> (or calloc() or realloc()). When your code executes free(temp),
> `temp' points to the "1" that initialized `i'. The memory
> holding that string was not obtained from malloc(), so you must
> not try to free() it.
>
> Aside: It is possible that the !strcmp(temp,"1") test is
> confusing you. You may have intended to call free() only when
> `temp' points to something other than "1", but the actual code
> does exactly the opposite: If `temp' points to something equal
> to "1", strcmp(temp,"1") returns zero to say that the strings
> are equal. Then the `!' converts that zero to one, which is
> "true" for the `if' test. A hasty reading of `if(!strcmp(...))'
> seems to say "Do something if the strings are not equal," but
> in fact it says "Do something if the strings *are* equal." For
> this reason (among others), I suggest you stop using the `!strcmp'
> form and write `if(strcmp(...) == 0)' or `if(strcmp(...) != 0)'
> to make your intent clearer.
>
Thanks a lot. That strcmp was the error.Thanks for pointing out .Thanks
again.

vaysagekv <> writes:

> On 09/09/12 7:02 PM, pete wrote:
>> vaysagekv wrote:
>>>
>>> I have a function like below.The program has compiled without any errors
>>> .But when I run it I am getting Error like this --->fibBigNumbers(186
>>> malloc: *** error for object 0x100000ee2: pointer being freed was not
>>> allocated
>>> *** set a breakpoint in malloc_error_break to debug
>>> 021Abort trap.
>>
>>> static char* i = "1";
>>> char* temp = i;
>>> free(temp);
>>
>> The argument in a call to free(),
>> should be a value which has previously been returned
>> by either malloc or calloc or realloc.
>> free() can also take a null pointer as an argument.
>>
> Hi,
> Thanks for the reply .Here the argument I have given to free is
> allocated by malloc in addBigNumbers function as below.
> char* addBigNumbers(char* first,char* second)
> {
> short lenOfFirst = strlen(first);
> short lenOfSecond = strlen(second);
> short len = lenOfFirst >= lenOfSecond ? lenOfFirst : lenOfSecond;
>
>
> char* result= malloc(len + 2);
> short resultLen = len + 1;
> if (result == NULL) {
> printf("Error");
> }
> result[resultLen] = '\0';
>
> .....
> .....
> .....
>
> return result;
>
> }
> Thanks
> vaysage

To get a useful reply, you need to tell us exactly what the code really
is. In your original post, the relevant lines were:

static char* i = "1";

char* temp = i;

free(temp);

so the only free() in that code was a variable that wasn't allocated
with malloc(). Now you're telling us that that wasn't the code at all,
that your variable was really malloc()ed inside your addBigNumbers()
function.

So -- what does the code really look like?

vaysagekv <> writes:
> On 09/09/12 7:02 PM, pete wrote:
>> vaysagekv wrote:
>>>
>>> I have a function like below.The program has compiled without any errors
>>> .But when I run it I am getting Error like this --->fibBigNumbers(186
>>> malloc: *** error for object 0x100000ee2: pointer being freed was not
>>> allocated
>>> *** set a breakpoint in malloc_error_break to debug
>>> 021Abort trap.
>>
>>> static char* i = "1";
>>> char* temp = i;
>>> free(temp);
>>
>> The argument in a call to free(),
>> should be a value which has previously been returned
>> by either malloc or calloc or realloc.
>> free() can also take a null pointer as an argument.
>>
> Thanks for the reply. Here the argument I have given to free is
> allocated by malloc in addBigNumbers function as below.
>
[snip]

For purposes of your question, it doesn't matter what addBigNumbers()
does. The argument you pass to free() is `temp`, which is initialized
to the value of `i`, which points to the first character of the string
literal "1".

Passing `i` as an argument to addBigNumbers() cannot change the value of
`i`.

In another followup you said something about the call to strcmp() being
the problem, but I don't think that would affect anything.

--
Keith Thompson (The_Other_Keith) kst- <http://www.ghoti.net/~kst>
Will write code for food.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"