Why is the use of alloca() not considered good pra

Question

alloca() allocates memory from Stack rather than heap which is case in malloc(). So, when I return from the routine the memory is freed. So, actually this solves my problem of freeing up of dynamically allocated memory. Freeing of memory allocated through malloc() is a major headache and if somehow missed leads to all sorts memory problems.

Why is the use of alloca() discouraged in spite of the above features?

Answer 1

Processes only have a limited amount of stack space available - far less than the amount of memory available to malloc().

By using alloca() you dramatically increase your chances of getting a Stack Overflow error (if you're lucky, or an inexplicable crash if you're not).