>mimus wrote:

>> On Wed, 30 Apr 2008 15:03:08 +0200, saneman wrote:
>>

>>> In the below code the last call to myprint does not work (gives a
>>> segmentation error).
>>>
>>> But I thought that pointer variables local in main (or any other
>>> function) would first be deleted when the calling function returns. Why
>>> does it give a segmentation fault?
>>>
>>>
>>>
>>> #include
>>> #include
>>>
>>> void myprint(double* a) {
>>> printf("number is = %%f\n",*a);
>>>
>>> }
>>>
>>>
>>>
>>> int main() {
>>>
>>> /* Working! (static allocation) */
>>> double d1 = 1.1;
>>> myprint(&d1);
>>>
>>> /* Working! (dynamic allocation) */
>>> double* d2 = (double*) malloc(sizeof(double*));
>>> *d2 = 2.2;
>>> myprint(d2);
>>>
>>> /* Not working! (why? main does not return!) */
>>> double* d3;
>>> *d3 = 3.3;
>>> myprint(d3);
>>>
>>>
>>> return 0;
>>>
>>> }

>>
>> Only three things I see:
>>
>> First, you shouldn't be declaring variables in the body of the program.
>>
>> Second, shouldn't your dynamic allocation of d2 use sizeof(double)?
>>
>> And third, you declare but don't set d3 _as a pointer_ before you use it
>> for indirection, wot I presume it's initialized to NULL and giving you
>> your segmentation fault:

>
>
>Ok so I need to make it point to something before setting the content?