[Asterisk-Dev] strdupa in app_voicemail2.c

[Thorsten Lockert]

ast_strdupa is not a function, but rather a macro (using GCC extensions),
that ultimately calls alloca & strcpy.

In fact, the ast_strdupa implementation in Asterisk is a verbatim copy
of the one provided in Linux.  As such it does require GCC to build, but
it will work on any system that provides an implementation of alloca.

Thorsten
--
Thorsten Lockert      | tholo at sigmasoft.com | Universe, n.:
2121 N. Lakeshore Dr. | tholo at openbsd.org   |         The problem.
Chapel Hill, NC 27514 |                     | 



-----Original Message-----
From: asterisk-dev-admin at lists.digium.com
[mailto:asterisk-dev-admin at lists.digium.com] On Behalf Of Tilghman Lesher
Sent: Friday, May 16, 2003 12:42
To: asterisk-dev at lists.digium.com
Subject: Re: [Asterisk-Dev] strdupa in app_voicemail2.c


On Friday 16 May 2003 10:25 am, Thorsten Lockert wrote:
> Some plain strdupa's snuck into the new voicemail system -- the
> attached diff changes these to use ast_strdupa like all other
> instances.

I'm curious to know how this can be done.  Given that strdupa relies
upon alloca, which is not a library function, but instead is a
compiler directive, how can it allocate space in a function, but
return that same space to a higher function without freeing it (as the
allocation was on the same stack which was just freed)?  What am I
missing here?

-Tilghman

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