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> My DataMessage structure is just a simple C structure for now. Is there a

quoted text
> recommended way of writing it to the ringbuffer given that I want to do

> something like this:

>

> void MessageQueue::push( DataMessage msg ){

>     // write to the ring buffer, converting DataMessage to a string

>     unsigned int written = jack_ringbuffer_write( mRingBuffer, (char *)

&msg

quoted text
> , sizeof(DataMessage) );

>    // etc

> }

as long as the struct is POD (Plain Old Data - no embedded pointers,

quoted text
> etc), this will work fine.

>

> however, you need to keep in mind that under some easily encounterable

> circumstances, the write may not return sizeof(DataMessage). this is a

> very easy mistake to make with ringbuffers (ditto for read).

>

> it can be avoided via careful sizing of the ringbuffer and always

> read/writing "whole objects" OR by carefully checking the results of

> read/write.

>

Thanks for the tips. What should one do if one detects a partial write? Is

it best to have integrity checks on both ends of the ringbuffer?
the jack ringbuffer design is particular bad in this respect because

quoted text
> it can only hold size-1 bytes (where size is its actual size).

>

Does this mean a good way to initialize it is to make the ringbuffer some

multiple of the sizeof(myMessageStruct) plus one byte?
Thanks again for all the help.

iain
--20cf303dd31202caba04b4056454

Content-Type: text/html; charset=ISO-8859-1

Content-Transfer-Encoding: quoted-printable
> My DataMessage structure is just a simple C structure for now. Is ther=

e a

quoted text
> recommended way of writing it to the ringbuffer given that I want to d=

o

quoted text
> something like this:

>

> void MessageQueue::push( DataMessage msg ){

> =A0 =A0 // write to the ring buffer, converting DataMessage to a strin=

g

quoted text
> =A0 =A0 unsigned int written =3D jack_ringbuffer_write( mRingBuffer, (=

char *) &msg

quoted text
> , sizeof(DataMessage) );

> =A0 =A0// etc

> }

as long as the st=

ruct is POD (Plain Old Data - no embedded pointers,

etc), this will work fine.
however, you need to keep in mind that under some easily encounterable

circumstances, the write may not return sizeof(DataMessage). this is a

very easy mistake to make with ringbuffers (ditto for read).
it can be avoided via careful sizing of the ringbuffer and always

read/writing "whole objects" OR by carefully checking the results=

 of

read/write.Thanks for the tips. What s=

hould one do if one detects a partial write? Is it best to have integrity c=

hecks on both ends of the ringbuffer?
the jack ringbuffer design is particular bad in this respect because

it can only hold size-1 bytes (where size is its actual size).Does this mean a good way to initialize it is to ma=

ke the ringbuffer some multiple of the sizeof(myMessageStruct) plus one byt=

e?

Thanks again for all the help.iain
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