3.2.5.3 Disadvantages of alloca

These are the disadvantages of alloca in comparison with malloc:

• If you try to allocate more memory than the machine can provide, you don't get a clean error message. Instead you get a fatal signal like the one you would get from an infinite recursion; probably a segmentation violation (see Program Error Signals).
• Some non-GNU systems fail to support alloca, so it is less portable. However, a slower emulation of alloca written in C is available for use on systems with this deficiency.