Thread: C - realloc() I Keep getting Segmentation fault (core dumped)

Originally Posted by Hodor

I think there is a typo here:


Should really be using __builtin_clzll otherwise the calculation will be incorrect. Also, I believe, that sizeof(size_t) should be multiplied to get the number of bits in size_t. (also added john.c's suggestion)

Code:

    new_capacity = 1ULL << ( sizeof ( size_t ) * CHAR_BIT - __builtin_clzll( needed - 1 ));

Although it's clear I think it's important to mention that it's not portable code

You are right: __builtin_clzll() and it is not portable... and I forgot sizeof returns the number of bytes, so I need to multiply sizeof( size_t ) by 8 as well...

There is a small confusion with the use of CHAR_BIT... this is the number of bits of char type. A byte is defined as 8 bits long (since 1960's I believe).

Thanks, anyway, for the correction!