UNW_SET_CACHING_POLICY(3)				       Programming Library					 UNW_SET_CACHING_POLICY(3)

NAME

       unw_set_caching_policy -- set unwind caching policy

SYNOPSIS

       #include <libunwind.h>

       int unw_set_caching_policy(unw_addr_space_t as, unw_caching_policy_t policy);

DESCRIPTION

       The  unw_set_caching_policy()  routine  sets the caching policy of address space as to the policy specified by argument policy.	The policy
       argument can take one of three possible values:

       UNW_CACHE_NONE
	       Turns off caching completely. This also implicitly flushes the contents of all caches as if unw_flush_cache() had been called.

       UNW_CACHE_GLOBAL
	       Enables caching using a global cache that is shared by all threads. If global caching is unavailable or unsupported, libunwind  may
	      fall back on using a per-thread cache, as if UNW_CACHE_PER_THREAD had been specified.

       UNW_CACHE_PER_THREAD
	       Enables	caching  using	thread-local  caches. If a thread-local caching are unavailable or unsupported, libunwind may fall back on
	      using a global cache, as if UNW_CACHE_GLOBAL had been specified.

       If caching is enabled, an application must be prepared to make appropriate calls to unw_flush_cache() whenever the target changes in a  way
       that  could  affect  the validity of cached information.  For example, after unloading (removing) a shared library, unw_flush_cache() would
       have to be called (at least) for the address-range that was covered by the shared library.

       For  address  spaces  created  via  unw_create_addr_space(3),  caching  is  turned  off	by  default.   For   the   local   address   space
       unw_local_addr_space, caching is turned on by default.

RETURN VALUE

       On successful completion, unw_set_caching_policy() returns 0.  Otherwise the negative value of one of the error-codes below is returned.

THREAD AND SIGNAL SAFETY

       unw_set_caching_policy() is thread-safe but not safe to use from a signal handler.

ERRORS

       UNW_ENOMEM
	       The desired caching policy could not be established because the application is out of memory.

SEE ALSO

       libunwind(3), unw_create_addr_space(3), unw_flush_cache(3)

AUTHOR

       David Mosberger-Tang
       Email: dmosberger@gmail.com
       WWW: http://www.nongnu.org/libunwind/.

Programming Library						  16 August 2007					 UNW_SET_CACHING_POLICY(3)