[alsa-devel] Scope of snd_pcm_hw_params_alloca() ?

Alan Horstmann gineera at aspect135.co.uk
Thu Mar 13 17:21:51 CET 2008

I've spent a couple of days pining this down.

snd_pcm_hw_params_alloca() is part of the user API -right?  But accomplished 
as a #define in pcm.h.

However if it is called inside a function, and the pointer stored for future 
use, after leaving the function the allocation seems to have gone, and 
attempting thereafter to use the pointer to access the hwparams space in 
another API function results in seg-fault.

This seems rather counter-intuitive (ie unexpected) to someone who has no 
knowledge of the inner workings, but simply uses the API; the allocation 
disappears without having been specifically free'd or released in any way.  I 
know that calling it globally gets round the problem, but certainly I could 
do without all the debug needed to discover that.



More information about the Alsa-devel mailing list