unw_set_caching_policy man page

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/.

Referenced By

libunwind(3), unw_flush_cache(3).

16 August 2007 Programming Library