alloc

Allocates a block of memory from the slice allocator.

The block address handed out can be expected to be aligned to at least `1 * sizeof (void*)`, though in general slices are `2 * sizeof ( void*)` bytes aligned; if a `malloc()` fallback implementation is used instead, the alignment may be reduced in a libc dependent fashion.

Note that the underlying slice allocation mechanism can be changed with the `G_SLICE=always-malloc` environment variable.

Parameters:

block_size

the number of bytes to allocate

Returns:

a pointer to the allocated memory block, which will be null if and only if mem_size is 0