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PMEMBLK_CTL_GET(3)	   PMDK	Programmer's Manual	    PMEMBLK_CTL_GET(3)

NAME
       pmemblk_ctl_get(),  pmemblk_ctl_set(),  pmemblk_ctl_exec()  - Query and
       modify libpmemblk internal behavior (EXPERIMENTAL)

SYNOPSIS
	      #include <libpmemblk.h>

	      int pmemblk_ctl_get(PMEMblkpool *pbp, const char *name, void *arg); (EXPERIMENTAL)
	      int pmemblk_ctl_set(PMEMblkpool *pbp, const char *name, void *arg); (EXPERIMENTAL)
	      int pmemblk_ctl_exec(PMEMblkpool *pbp, const char	*name, void *arg); (EXPERIMENTAL)

DESCRIPTION
       The pmemblk_ctl_get(), pmemblk_ctl_set()	and  pmemblk_ctl_exec()	 func-
       tions provide a uniform interface for querying and modifying the	inter-
       nal behavior of libpmemblk(7) through the control (CTL) namespace.

       The name	argument specifies an entry point as defined in	the CTL	 name-
       space specification.  The entry point description specifies whether the
       extra arg is required.  Those two  parameters  together	create	a  CTL
       query.  The functions and the entry points are thread-safe unless indi-
       cated otherwise below.  If there	are special conditions for calling  an
       entry  point, they are explicitly stated	in its description.  The func-
       tions propagate the return value	of the entry point.  If	either name or
       arg is invalid, -1 is returned.

       If  the	provided ctl query is valid, the CTL functions will always re-
       turn 0 on success and -1	on failure, unless otherwise specified in  the
       entry point description.

       See more	in pmem_ctl(5) man page.

CTL NAMESPACE
       prefault.at_create | rw | global	| int |	int | -	| boolean

       If  set,	every page of the pool will be touched and written to when the
       pool is created,	in order to trigger page allocation and	 minimize  the
       performance  impact  of	pagefaults.  Affects only the pmemblk_create()
       function.

       Always returns 0.

       prefault.at_open	| rw | global |	int | int | - |	boolean

       If set, every page of the pool will be touched and written to when  the
       pool  is	 opened,  in order to trigger page allocation and minimize the
       performance impact of  pagefaults.   Affects  only  the	pmemblk_open()
       function.

       Always returns 0.

       sds.at_create | rw | global | int | int | - | boolean

       If  set,	 force-enables	or force-disables SDS feature during pool cre-
       ation.  Affects only the	pmemblk_create() function.  See	 pmempool_fea-
       ture_query(3) for informations about SDS	(SHUTDOWN_STATE) feature.

       Always returns 0.

       copy_on_write.at_open | rw | global | int | int | - | boolean

       If set, pool is mapped in such a	way that modifications don't reach the
       underlying medium.  From	the user's perspective this  means  that  when
       the  pool is closed all changes are reverted.  This feature is not sup-
       ported for pools	located	on Device DAX.

       Always returns 0.

CTL EXTERNAL CONFIGURATION
       In addition to direct function call, each write entry point can also be
       set using two alternative methods.

       The  first  method  is  to load a configuration directly	from the PMEM-
       BLK_CONF	environment variable.

       The second method of loading an external	configuration is  to  set  the
       PMEMBLK_CONF_FILE environment variable to point to a file that contains
       a sequence of ctl queries.

       See more	in pmem_ctl(5) man page.

SEE ALSO
       libpmemblk(7), pmem_ctl(5) and <http://pmem.io>

PMDK - pmemblk API version 1.1	  2019-07-10		    PMEMBLK_CTL_GET(3)

NAME | SYNOPSIS | DESCRIPTION | CTL NAMESPACE | CTL EXTERNAL CONFIGURATION | SEE ALSO

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