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Modules

 Pool Cleanup Functions
 
 Pool Debugging functions.
 

Macros

#define APR_POOL_DECLARE_ACCESSOR(type)
 
#define APR_POOL_IMPLEMENT_ACCESSOR(type)
 
#define APR_POOL__FILE_LINE__   __FILE__ ":" APR_STRINGIFY(__LINE__)
 

Typedefs

typedef struct apr_pool_t apr_pool_t
 
typedef int(* apr_abortfunc_t )(int retcode)
 

Functions

apr_status_t apr_pool_initialize (void)
 
void apr_pool_terminate (void)
 
apr_status_t apr_pool_create_ex (apr_pool_t **newpool, apr_pool_t *parent, apr_abortfunc_t abort_fn, apr_allocator_t *allocator)
 
apr_status_t apr_pool_create_core_ex (apr_pool_t **newpool, apr_abortfunc_t abort_fn, apr_allocator_t *allocator)
 
apr_status_t apr_pool_create_unmanaged_ex (apr_pool_t **newpool, apr_abortfunc_t abort_fn, apr_allocator_t *allocator)
 
apr_status_t apr_pool_create_ex_debug (apr_pool_t **newpool, apr_pool_t *parent, apr_abortfunc_t abort_fn, apr_allocator_t *allocator, const char *file_line)
 
apr_status_t apr_pool_create_core_ex_debug (apr_pool_t **newpool, apr_abortfunc_t abort_fn, apr_allocator_t *allocator, const char *file_line)
 
apr_status_t apr_pool_create_unmanaged_ex_debug (apr_pool_t **newpool, apr_abortfunc_t abort_fn, apr_allocator_t *allocator, const char *file_line)
 
apr_status_t apr_pool_create (apr_pool_t **newpool, apr_pool_t *parent)
 
apr_status_t apr_pool_create_core (apr_pool_t **newpool)
 
apr_status_t apr_pool_create_unmanaged (apr_pool_t **newpool)
 
apr_allocator_tapr_pool_allocator_get (apr_pool_t *pool)
 
void apr_pool_clear (apr_pool_t *p)
 
void apr_pool_clear_debug (apr_pool_t *p, const char *file_line)
 
void apr_pool_destroy (apr_pool_t *p)
 
void apr_pool_destroy_debug (apr_pool_t *p, const char *file_line)
 
void * apr_palloc (apr_pool_t *p, apr_size_t size)
 
void * apr_palloc_debug (apr_pool_t *p, apr_size_t size, const char *file_line)
 
void * apr_pcalloc (apr_pool_t *p, apr_size_t size)
 
void * apr_pcalloc_debug (apr_pool_t *p, apr_size_t size, const char *file_line)
 
void apr_pool_abort_set (apr_abortfunc_t abortfunc, apr_pool_t *pool)
 
apr_abortfunc_t apr_pool_abort_get (apr_pool_t *pool)
 
apr_pool_tapr_pool_parent_get (apr_pool_t *pool)
 
int apr_pool_is_ancestor (apr_pool_t *a, apr_pool_t *b)
 
void apr_pool_tag (apr_pool_t *pool, const char *tag)
 
apr_status_t apr_pool_userdata_set (const void *data, const char *key, apr_status_t(*cleanup)(void *), apr_pool_t *pool)
 
apr_status_t apr_pool_userdata_setn (const void *data, const char *key, apr_status_t(*cleanup)(void *), apr_pool_t *pool)
 
apr_status_t apr_pool_userdata_get (void **data, const char *key, apr_pool_t *pool)
 

Detailed Description

Macro Definition Documentation

#define APR_POOL__FILE_LINE__   __FILE__ ":" APR_STRINGIFY(__LINE__)

Pool debug levels

| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |

|   |   |   |   |   |   |   | x |  General debug code enabled (useful in
                                   combination with –with-efence).
|   |   |   |   |   |   | x |   |  Verbose output on stderr (report
                                   CREATE, CLEAR, DESTROY).
|   |   |   | x |   |   |   |   |  Verbose output on stderr (report
                                   PALLOC, PCALLOC).
|   |   |   |   |   | x |   |   |  Lifetime checking. On each use of a
                                   pool, check its lifetime.  If the pool
                                   is out of scope, abort().
                                   In combination with the verbose flag
                                   above, it will output LIFE in such an
                                   event prior to aborting.
|   |   |   |   | x |   |   |   |  Pool owner checking.  On each use of a
                                   pool, check if the current thread is the
                                   pool's owner.  If not, abort().  In
                                   combination with the verbose flag above,
                                   it will output OWNER in such an event
                                   prior to aborting.  Use the debug
                                   function apr_pool_owner_set() to switch
                                   a pool's ownership.
When no debug level was specified, assume general debug mode.
If level 0 was specified, debugging is switched off.

the place in the code where the particular function was called

#define APR_POOL_DECLARE_ACCESSOR (   type)
Value:
APR_DECLARE(apr_pool_t *) apr_##type##_pool_get \
(const apr_##type##_t *the##type)

Declaration helper macro to construct apr_foo_pool_get()s.

This standardized macro is used by opaque (APR) data types to return the apr_pool_t that is associated with the data type.

APR_POOL_DECLARE_ACCESSOR() is used in a header file to declare the accessor function. A typical usage and result would be:

   APR_POOL_DECLARE_ACCESSOR(file);
becomes:
   APR_DECLARE(apr_pool_t *) apr_file_pool_get(const apr_file_t *thefile);
Remarks
Doxygen unwraps this macro (via doxygen.conf) to provide actual help for each specific occurrence of apr_foo_pool_get.
the linkage is specified for APR. It would be possible to expand the macros to support other linkages.
#define APR_POOL_IMPLEMENT_ACCESSOR (   type)
Value:
APR_DECLARE(apr_pool_t *) apr_##type##_pool_get \
(const apr_##type##_t *the##type) \
{ return the##type->pool; }

Implementation helper macro to provide apr_foo_pool_get()s.

In the implementation, the APR_POOL_IMPLEMENT_ACCESSOR() is used to actually define the function. It assumes the field is named "pool".

Typedef Documentation

typedef int(* apr_abortfunc_t)(int retcode)

A function that is called when allocation fails.

typedef struct apr_pool_t apr_pool_t

The fundamental pool type

Function Documentation

void* apr_palloc ( apr_pool_t p,
apr_size_t  size 
)

Allocate a block of memory from a pool

Parameters
pThe pool to allocate from
sizeThe amount of memory to allocate
Returns
The allocated memory
void* apr_palloc_debug ( apr_pool_t p,
apr_size_t  size,
const char *  file_line 
)

Debug version of apr_palloc

Parameters
pSee: apr_palloc
sizeSee: apr_palloc
file_lineWhere the function is called from. This is usually APR_POOL__FILE_LINE__.
Returns
See: apr_palloc
void* apr_pcalloc ( apr_pool_t p,
apr_size_t  size 
)

Allocate a block of memory from a pool and set all of the memory to 0

Parameters
pThe pool to allocate from
sizeThe amount of memory to allocate
Returns
The allocated memory
void* apr_pcalloc_debug ( apr_pool_t p,
apr_size_t  size,
const char *  file_line 
)

Debug version of apr_pcalloc

Parameters
pSee: apr_pcalloc
sizeSee: apr_pcalloc
file_lineWhere the function is called from. This is usually APR_POOL__FILE_LINE__.
Returns
See: apr_pcalloc
apr_abortfunc_t apr_pool_abort_get ( apr_pool_t pool)

Get the abort function associated with the specified pool.

Parameters
poolThe pool for retrieving the abort function.
Returns
The abort function for the given pool.
void apr_pool_abort_set ( apr_abortfunc_t  abortfunc,
apr_pool_t pool 
)

Set the function to be called when an allocation failure occurs.

Remarks
If the program wants APR to exit on a memory allocation error, then this function can be called to set the callback to use (for performing cleanup and then exiting). If this function is not called, then APR will return an error and expect the calling program to deal with the error accordingly.
apr_allocator_t* apr_pool_allocator_get ( apr_pool_t pool)

Find the pool's allocator

Parameters
poolThe pool to get the allocator from.
void apr_pool_clear ( apr_pool_t p)

Clear all memory in the pool and run all the cleanups. This also destroys all subpools.

Parameters
pThe pool to clear
Remarks
This does not actually free the memory, it just allows the pool to re-use this memory for the next allocation.
See Also
apr_pool_destroy()
void apr_pool_clear_debug ( apr_pool_t p,
const char *  file_line 
)

Debug version of apr_pool_clear.

Parameters
pSee: apr_pool_clear.
file_lineWhere the function is called from. This is usually APR_POOL__FILE_LINE__.
Remarks
Only available when APR_POOL_DEBUG is defined. Call this directly if you have your apr_pool_clear calls in a wrapper function and wish to override the file_line argument to reflect the caller of your wrapper function. If you do not have apr_pool_clear in a wrapper, trust the macro and don't call apr_pool_destroy_clear directly.
apr_status_t apr_pool_create ( apr_pool_t **  newpool,
apr_pool_t parent 
)

Create a new pool.

Parameters
newpoolThe pool we have just created.
parentThe parent pool. If this is NULL, the new pool is a root pool. If it is non-NULL, the new pool will inherit all of its parent pool's attributes, except the apr_pool_t will be a sub-pool.
Remarks
This function is thread-safe, in the sense that multiple threads can safely create subpools of the same parent pool concurrently. Similarly, a subpool can be created by one thread at the same time that another thread accesses the parent pool.
apr_status_t apr_pool_create_core ( apr_pool_t **  newpool)

Create a new unmanaged pool.

Parameters
newpoolThe pool we have just created.
apr_status_t apr_pool_create_core_ex ( apr_pool_t **  newpool,
apr_abortfunc_t  abort_fn,
apr_allocator_t allocator 
)

Create a new pool.

Deprecated:
See Also
apr_pool_create_unmanaged_ex.
apr_status_t apr_pool_create_core_ex_debug ( apr_pool_t **  newpool,
apr_abortfunc_t  abort_fn,
apr_allocator_t allocator,
const char *  file_line 
)

Debug version of apr_pool_create_core_ex.

Deprecated:
See Also
apr_pool_create_unmanaged_ex_debug.
apr_status_t apr_pool_create_ex ( apr_pool_t **  newpool,
apr_pool_t parent,
apr_abortfunc_t  abort_fn,
apr_allocator_t allocator 
)

Create a new pool.

Parameters
newpoolThe pool we have just created.
parentThe parent pool. If this is NULL, the new pool is a root pool. If it is non-NULL, the new pool will inherit all of its parent pool's attributes, except the apr_pool_t will be a sub-pool.
abort_fnA function to use if the pool cannot allocate more memory.
allocatorThe allocator to use with the new pool. If NULL the allocator of the parent pool will be used.
Remarks
This function is thread-safe, in the sense that multiple threads can safely create subpools of the same parent pool concurrently. Similarly, a subpool can be created by one thread at the same time that another thread accesses the parent pool.
apr_status_t apr_pool_create_ex_debug ( apr_pool_t **  newpool,
apr_pool_t parent,
apr_abortfunc_t  abort_fn,
apr_allocator_t allocator,
const char *  file_line 
)

Debug version of apr_pool_create_ex.

Parameters
newpool@seeapr_pool_create.
parent@seeapr_pool_create.
abort_fn@seeapr_pool_create.
allocator@seeapr_pool_create.
file_lineWhere the function is called from. This is usually APR_POOL__FILE_LINE__.
Remarks
Only available when APR_POOL_DEBUG is defined. Call this directly if you have your apr_pool_create_ex calls in a wrapper function and wish to override the file_line argument to reflect the caller of your wrapper function. If you do not have apr_pool_create_ex in a wrapper, trust the macro and don't call apr_pool_create_ex_debug directly.
apr_status_t apr_pool_create_unmanaged_ex ( apr_pool_t **  newpool,
apr_abortfunc_t  abort_fn,
apr_allocator_t allocator 
)

Create a new unmanaged pool.

Parameters
newpoolThe pool we have just created.
abort_fnA function to use if the pool cannot allocate more memory.
allocatorThe allocator to use with the new pool. If NULL a new allocator will be created with the new pool as owner.
Remarks
An unmanaged pool is a special pool without a parent; it will NOT be destroyed upon apr_terminate. It must be explicitly destroyed by calling apr_pool_destroy, to prevent memory leaks. Use of this function is discouraged, think twice about whether you really really need it.
Warning
Any child cleanups registered against the new pool, or against sub-pools thereof, will not be executed during an invocation of apr_proc_create(), so resources created in an "unmanaged" pool hierarchy will leak to child processes.
apr_status_t apr_pool_create_unmanaged_ex_debug ( apr_pool_t **  newpool,
apr_abortfunc_t  abort_fn,
apr_allocator_t allocator,
const char *  file_line 
)

Debug version of apr_pool_create_unmanaged_ex.

Parameters
newpool@seeapr_pool_create_unmanaged.
abort_fn@seeapr_pool_create_unmanaged.
allocator@seeapr_pool_create_unmanaged.
file_lineWhere the function is called from. This is usually APR_POOL__FILE_LINE__.
Remarks
Only available when APR_POOL_DEBUG is defined. Call this directly if you have your apr_pool_create_unmanaged_ex calls in a wrapper function and wish to override the file_line argument to reflect the caller of your wrapper function. If you do not have apr_pool_create_core_ex in a wrapper, trust the macro and don't call apr_pool_create_core_ex_debug directly.
void apr_pool_destroy ( apr_pool_t p)

Destroy the pool. This takes similar action as apr_pool_clear() and then frees all the memory.

Parameters
pThe pool to destroy
Remarks
This will actually free the memory
void apr_pool_destroy_debug ( apr_pool_t p,
const char *  file_line 
)

Debug version of apr_pool_destroy.

Parameters
pSee: apr_pool_destroy.
file_lineWhere the function is called from. This is usually APR_POOL__FILE_LINE__.
Remarks
Only available when APR_POOL_DEBUG is defined. Call this directly if you have your apr_pool_destroy calls in a wrapper function and wish to override the file_line argument to reflect the caller of your wrapper function. If you do not have apr_pool_destroy in a wrapper, trust the macro and don't call apr_pool_destroy_debug directly.
apr_status_t apr_pool_initialize ( void  )

Setup all of the internal structures required to use pools

Remarks
Programs do NOT need to call this directly. APR will call this automatically from apr_initialize.
int apr_pool_is_ancestor ( apr_pool_t a,
apr_pool_t b 
)

Determine if pool a is an ancestor of pool b.

Parameters
aThe pool to search
bThe pool to search for
Returns
True if a is an ancestor of b, NULL is considered an ancestor of all pools.
Remarks
if compiled with APR_POOL_DEBUG, this function will also return true if A is a pool which has been guaranteed by the caller (using apr_pool_join) to have a lifetime at least as long as some ancestor of pool B.
apr_pool_t* apr_pool_parent_get ( apr_pool_t pool)

Get the parent pool of the specified pool.

Parameters
poolThe pool for retrieving the parent pool.
Returns
The parent of the given pool.
void apr_pool_tag ( apr_pool_t pool,
const char *  tag 
)

Tag a pool (give it a name)

Parameters
poolThe pool to tag
tagThe tag
void apr_pool_terminate ( void  )

Tear down all of the internal structures required to use pools

Remarks
Programs do NOT need to call this directly. APR will call this automatically from apr_terminate.
apr_status_t apr_pool_userdata_get ( void **  data,
const char *  key,
apr_pool_t pool 
)

Return the data associated with the current pool.

Parameters
dataThe user data associated with the pool.
keyThe key for the data to retrieve
poolThe current pool.
apr_status_t apr_pool_userdata_set ( const void *  data,
const char *  key,
apr_status_t(*)(void *)  cleanup,
apr_pool_t pool 
)

Set the data associated with the current pool

Parameters
dataThe user data associated with the pool.
keyThe key to use for association
cleanupThe cleanup program to use to cleanup the data (NULL if none)
poolThe current pool
Warning
The data to be attached to the pool should have a life span at least as long as the pool it is being attached to.

Users of APR must take EXTREME care when choosing a key to use for their data. It is possible to accidentally overwrite data by choosing a key that another part of the program is using. Therefore it is advised that steps are taken to ensure that unique keys are used for all of the userdata objects in a particular pool (the same key in two different pools or a pool and one of its subpools is okay) at all times. Careful namespace prefixing of key names is a typical way to help ensure this uniqueness.

apr_status_t apr_pool_userdata_setn ( const void *  data,
const char *  key,
apr_status_t(*)(void *)  cleanup,
apr_pool_t pool 
)

Set the data associated with the current pool

Parameters
dataThe user data associated with the pool.
keyThe key to use for association
cleanupThe cleanup program to use to cleanup the data (NULL if none)
poolThe current pool
Note
same as apr_pool_userdata_set(), except that this version doesn't make a copy of the key (this function is useful, for example, when the key is a string literal)
Warning
This should NOT be used if the key could change addresses by any means between the apr_pool_userdata_setn() call and a subsequent apr_pool_userdata_get() on that key, such as if a static string is used as a userdata key in a DSO and the DSO could be unloaded and reloaded between the _setn() and the _get(). You MUST use apr_pool_userdata_set() in such cases.
More generally, the key and the data to be attached to the pool should have a life span at least as long as the pool itself.