Hi, Ahelenia!

On 8/24/21 12:33 PM, Alejandro Colomar (man-pages) wrote:

And apart from what Michael (and Branden) already said, I have one 
question that has not been treated before it seems:

AFAIK, VLAs are 100% equivalent to alloca() (except for the obvious 
syntax differences).  And considering the VLA syntax is much nicer than 
alloca(), and is in the standard (IIRC, C99 added VLAs, and C11 declared 
them optional), what about adding a NOTES subsection that recommends (or 
at least mentions) VLAs?

And they both share the problem of smashing the stack if you try to 
allocate an array to big (and none of them has a way to check if it will 
happen, AFAIK).

Now that I think, there's a slight difference, of course:  VLAs live in 
their block scope, while alloca() lives in the function scope, allowing 
to embed it in a macro such as strdupa().

But maybe still worth mentioning VLAs in alloca(3).

Cheers,

Alex


-- 
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/