According to the man ( http://pubs.opengroup.org/onlinepubs/009696899/functions/ftok.html), ftok() uses only the low-order 8-bits of the id. Maybe the APR could use the last char of the filename instead, so that the users knows and can choose it. For APR's internal/choosen filenames (if any), this byte could be generated randomly.
On Fri, Jan 24, 2014 at 10:57 PM, Jim Jagielski <[email protected]> wrote: > On httpd there was a discussion regarding versioning, and > this got me thinking... > > Included in the APR 1.5.1 changes is an internal change > to how apr_shm_create(), when using APR_USE_SHMEM_SHMGET, > calculates the key (via ftok())... > > The problem (see the Bugz report) was that using the constant > 1 would cause collisions, so I adjusted it to use a hash > of the filename. The problem there is that any external > APR users that needed to also determine the key needs to > be aware of that. And from what I can see, there is no > easy way to do that. > > So I will be pulling that from 2.0-dev and 1.5-dev until > we can figure out a better way. Ideas appreciated. >
