IIRC, bit fields are normally int-word sized.
On Apr 29, 2013, at 12:03 PM, Graham Leggett <[email protected]> wrote:
> Hi all,
>
> A number of the modules have flags, and with additions typically over time
> the flags end up looking like this, which takes up a lot of space:
>
> struct {
> [variable]
> [flag]
> [variable]
> [flag]
> …
> }
>
> Would it make sense to group the flags at the beginning, in theory allowing
> us to add flags without breaking the ABI?
>
> struct {
> [flag:1]
> [flag:1}
> … (within reason, 32 flags max?)
> [variable]
> [variable]
> …
> }
>
> Is it safe to practically assume that the bit field will be at least 32 bits
> wide, or are there cases were we might see a 16 bit word?
>
> Something like this:
>
> Index: modules/proxy/mod_proxy.h
> ===================================================================
> --- modules/proxy/mod_proxy.h (revision 1476661)
> +++ modules/proxy/mod_proxy.h (working copy)
> @@ -128,6 +128,22 @@
> };
>
> typedef struct {
> + unsigned int req_set:1;
> + unsigned int viaopt_set:1;
> + unsigned int recv_buffer_size_set:1;
> + unsigned int io_buffer_size_set:1;
> + unsigned int maxfwd_set:1;
> + unsigned int timeout_set:1;
> + unsigned int badopt_set:1;
> + unsigned int proxy_status_set:1;
> + unsigned int source_address_set:1;
> + unsigned int bgrowth_set:1;
> + unsigned int bal_persist:1;
> + unsigned int inherit:1;
> + unsigned int inherit_set:1;
> + unsigned int ppinherit:1;
> + unsigned int ppinherit_set:1;
> +
> apr_array_header_t *proxies;
> apr_array_header_t *sec_proxy;
> apr_array_header_t *aliases;
> @@ -168,25 +184,25 @@
> ap_slotmem_instance_t *bslot; /* balancers shm data - runtime */
> ap_slotmem_provider_t *storage;
>
> - unsigned int req_set:1;
> - unsigned int viaopt_set:1;
> - unsigned int recv_buffer_size_set:1;
> - unsigned int io_buffer_size_set:1;
> - unsigned int maxfwd_set:1;
> - unsigned int timeout_set:1;
> - unsigned int badopt_set:1;
> - unsigned int proxy_status_set:1;
> - unsigned int source_address_set:1;
> - unsigned int bgrowth_set:1;
> - unsigned int bal_persist:1;
> - unsigned int inherit:1;
> - unsigned int inherit_set:1;
> - unsigned int ppinherit:1;
> - unsigned int ppinherit_set:1;
> } proxy_server_conf;
>
>
> typedef struct {
> + /**
> + * the following setting masks the error page
> + * returned from the 'proxied server' and just
> + * forwards the status code upwards.
> + * This allows the main server (us) to generate
> + * the error page, (so it will look like a error
> + * returned from the rest of the system
> + */
> + unsigned int error_override:1;
> + unsigned int preserve_host:1;
> + unsigned int preserve_host_set:1;
> + unsigned int error_override_set:1;
> + unsigned int alias_set:1;
> + unsigned int add_forwarded_headers:1;
> +
> const char *p; /* The path */
> ap_regex_t *r; /* Is this a regex? */
>
> @@ -205,20 +221,6 @@
> signed char interpolate_env;
> struct proxy_alias *alias;
>
> - /**
> - * the following setting masks the error page
> - * returned from the 'proxied server' and just
> - * forwards the status code upwards.
> - * This allows the main server (us) to generate
> - * the error page, (so it will look like a error
> - * returned from the rest of the system
> - */
> - unsigned int error_override:1;
> - unsigned int preserve_host:1;
> - unsigned int preserve_host_set:1;
> - unsigned int error_override_set:1;
> - unsigned int alias_set:1;
> - unsigned int add_forwarded_headers:1;
> } proxy_dir_conf;
>
> /* if we interpolate env vars per-request, we'll need a per-request
>
> Regards,
> Graham
> --
>
