Compatibility header for alloca. More...

Detailed Description

Compatibility header for alloca.

This header provides an alloca-like function using variable-length arrays (VLAs), a built-in alloca function, or using malloc.

Two functions are provided:

cal_alloca(type, var, count)
cal_freea(var)

These functions should always be used like this:

void my_function(size_t count)
{
    cal_alloca(double, mybuf, count);

do something with mybuf ... cal_freea(mybuf); }

Do not use cal_alloca anywhere except in the outermost scope of a function, as VLAs and alloca have different lifetimes. Additionally, cal_freea must (and can only) be called right before the function returns. Using longjmp with to jump out of any function that uses cal_alloca causes undefined behavior.

This header can be included multiple times.