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Passing a variable from one function to another.


Anonymous

Anonymous
Aug 1, 2011 at 10:46pm

Hello,

you can do something like that (even if IMHO you should avoid to free/alloc memory each time) ;
you don’t need to use float *storage = x->storage ;
correct me if i didn’t understand your problem.

...

sysmem_freeptr (x->storage);
x->storage = (float *)sysmem_newptr (totalframes * b_nchans * sizeof(float)); 

memcpy (x->storage, b_samples + (startframe * b_nchans), totalframes * b_nchans * sizeof(float));

n = totalframes;

fbuf_paste (x, n);
}
...

fbuf_paste (t_myObject *x, long n)
{
float *toto = x->storage;
...
}

HTH

#58307

nicolas danet

nicolas danet
Aug 2, 2011 at 8:46am

Hello,

“You mentioned I should avoid free/alloc each time, I know this could lead to instability issues, what would you suggest?”

AFAIK : not an instability issue, but speed issue ; allocate a big one and reallocate it only in case of overflow.

“Do I need to implement a routine that waits for the buffer to update before any further action can take place ?”

Timothy Place wrote a nice paper on it, in his object74 blog ; or have a look on maxMSP t_buffer entry.
To sum up : YES, there is an ATOMIC lock to set/unset accessing the buffer.

http://74objects.com/2009/03/22/accessing-buffers/

HTH

#209478

nicolas danet

nicolas danet
Aug 2, 2011 at 9:06am

Hello again ;-)

“I’ve also noticed if I replace ‘memcopy’ with ‘sysmem_copyptr’ it doesn’t store any of the buffer, I’m I missing something ?

Take care, (if i’m not wrong), source and destination pointer are reversed.

More generally, when you have a question please try first to search in old threads ; as you can find severals about buffers access ;-)

Ciao.

#209479

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