Apache Portable Runtime
Data Structures | Defines | Typedefs | Enumerations | Functions
Poll Routines
Apache Portability Runtime library

Data Structures

union  apr_descriptor
struct  apr_pollfd_t

Defines

#define APR_POLLIN   0x001
#define APR_POLLPRI   0x002
#define APR_POLLOUT   0x004
#define APR_POLLERR   0x010
#define APR_POLLHUP   0x020
#define APR_POLLNVAL   0x040
#define APR_POLLSET_THREADSAFE   0x001
#define APR_POLLSET_NOCOPY   0x002
#define APR_POLLSET_WAKEABLE   0x004
#define APR_POLLSET_NODEFAULT   0x010

Typedefs

typedef struct apr_pollfd_t apr_pollfd_t
typedef struct apr_pollset_t apr_pollset_t
typedef struct apr_pollcb_t apr_pollcb_t
typedef apr_status_t(* apr_pollcb_cb_t )(void *baton, apr_pollfd_t *descriptor)

Enumerations

enum  apr_pollset_method_e {
  APR_POLLSET_DEFAULT, APR_POLLSET_SELECT, APR_POLLSET_KQUEUE, APR_POLLSET_PORT,
  APR_POLLSET_EPOLL, APR_POLLSET_POLL
}
enum  apr_datatype_e { APR_NO_DESC, APR_POLL_SOCKET, APR_POLL_FILE, APR_POLL_LASTDESC }

Functions

apr_status_t apr_pollset_create (apr_pollset_t **pollset, apr_uint32_t size, apr_pool_t *p, apr_uint32_t flags)
apr_status_t apr_pollset_create_ex (apr_pollset_t **pollset, apr_uint32_t size, apr_pool_t *p, apr_uint32_t flags, apr_pollset_method_e method)
apr_status_t apr_pollset_destroy (apr_pollset_t *pollset)
apr_status_t apr_pollset_add (apr_pollset_t *pollset, const apr_pollfd_t *descriptor)
apr_status_t apr_pollset_remove (apr_pollset_t *pollset, const apr_pollfd_t *descriptor)
apr_status_t apr_pollset_poll (apr_pollset_t *pollset, apr_interval_time_t timeout, apr_int32_t *num, const apr_pollfd_t **descriptors)
apr_status_t apr_pollset_wakeup (apr_pollset_t *pollset)
apr_status_t apr_poll (apr_pollfd_t *aprset, apr_int32_t numsock, apr_int32_t *nsds, apr_interval_time_t timeout)
const char * apr_pollset_method_name (apr_pollset_t *pollset)
const char * apr_poll_method_defname (void)
apr_status_t apr_pollcb_create (apr_pollcb_t **pollcb, apr_uint32_t size, apr_pool_t *p, apr_uint32_t flags)
apr_status_t apr_pollcb_create_ex (apr_pollcb_t **pollcb, apr_uint32_t size, apr_pool_t *p, apr_uint32_t flags, apr_pollset_method_e method)
apr_status_t apr_pollcb_add (apr_pollcb_t *pollcb, apr_pollfd_t *descriptor)
apr_status_t apr_pollcb_remove (apr_pollcb_t *pollcb, apr_pollfd_t *descriptor)
apr_status_t apr_pollcb_poll (apr_pollcb_t *pollcb, apr_interval_time_t timeout, apr_pollcb_cb_t func, void *baton)
apr_status_t apr_pollcb_wakeup (apr_pollcb_t *pollcb)
const char * apr_pollcb_method_name (apr_pollcb_t *pollcb)

Define Documentation

#define APR_POLLERR   0x010

Pending error

#define APR_POLLHUP   0x020

Hangup occurred

#define APR_POLLIN   0x001

Poll options Can read without blocking

#define APR_POLLNVAL   0x040

Descriptor invalid

#define APR_POLLOUT   0x004

Can write without blocking

#define APR_POLLPRI   0x002

Priority data available

#define APR_POLLSET_NOCOPY   0x002

Descriptors passed to apr_pollset_add() are not copied

#define APR_POLLSET_NODEFAULT   0x010

Do not try to use the default method if the specified non-default method cannot be used

#define APR_POLLSET_THREADSAFE   0x001

Pollset Flags Adding or removing a descriptor is thread-safe

#define APR_POLLSET_WAKEABLE   0x004

Poll operations are interruptable by apr_pollset_wakeup() or apr_pollcb_wakeup()


Typedef Documentation

typedef apr_status_t(* apr_pollcb_cb_t)(void *baton, apr_pollfd_t *descriptor)

Function prototype for pollcb handlers

Parameters:
batonOpaque baton passed into apr_pollcb_poll()
descriptorContains the notification for an active descriptor. The rtnevents member describes which events were triggered for this descriptor.
Remarks:
If the pollcb handler does not return APR_SUCCESS, the apr_pollcb_poll() call returns with the handler's return value.
typedef struct apr_pollcb_t apr_pollcb_t

Opaque structure used for pollcb API

typedef struct apr_pollfd_t apr_pollfd_t
See also:
apr_pollfd_t
typedef struct apr_pollset_t apr_pollset_t

Opaque structure used for pollset API


Enumeration Type Documentation

Used in apr_pollfd_t to determine what the apr_descriptor is

Enumerator:
APR_NO_DESC 

nothing here

APR_POLL_SOCKET 

descriptor refers to a socket

APR_POLL_FILE 

descriptor refers to a file

APR_POLL_LASTDESC 
Deprecated:
descriptor is the last one in the list

Pollset Methods

Enumerator:
APR_POLLSET_DEFAULT 

Platform default poll method

APR_POLLSET_SELECT 

Poll uses select method

APR_POLLSET_KQUEUE 

Poll uses kqueue method

APR_POLLSET_PORT 

Poll uses Solaris event port method

APR_POLLSET_EPOLL 

Poll uses epoll method

APR_POLLSET_POLL 

Poll uses poll method


Function Documentation

apr_status_t apr_poll ( apr_pollfd_t aprset,
apr_int32_t  numsock,
apr_int32_t *  nsds,
apr_interval_time_t  timeout 
)

Poll the descriptors in the poll structure

Parameters:
aprsetThe poll structure we will be using.
numsockThe number of descriptors we are polling
nsdsThe number of descriptors signalled (output parameter)
timeoutThe amount of time in microseconds to wait. This is a maximum, not a minimum. If a descriptor is signalled, the function will return before this time. If timeout is negative, the function will block until a descriptor is signalled or until apr_pollset_wakeup() has been called.
Remarks:
The number of descriptors signalled is returned in the third argument. This is a blocking call, and it will not return until either a descriptor has been signalled or the timeout has expired.
The rtnevents field in the apr_pollfd_t array will only be filled- in if the return value is APR_SUCCESS.
const char* apr_poll_method_defname ( void  )

Return a printable representation of the default pollset method (APR_POLLSET_DEFAULT).

apr_status_t apr_pollcb_add ( apr_pollcb_t pollcb,
apr_pollfd_t descriptor 
)

Add a socket or file descriptor to a pollcb

Parameters:
pollcbThe pollcb to which to add the descriptor
descriptorThe descriptor to add
Remarks:
If you set client_data in the descriptor, that value will be returned in the client_data field whenever this descriptor is signalled in apr_pollcb_poll().
Unlike the apr_pollset API, the descriptor is not copied, and users must retain the memory used by descriptor, as the same pointer will be returned to them from apr_pollcb_poll.
Do not add the same socket or file descriptor to the same pollcb multiple times, even if the requested events differ for the different calls to apr_pollcb_add(). If the events of interest for a descriptor change, you must first remove the descriptor from the pollcb with apr_pollcb_remove(), then add it again specifying all requested events.
apr_status_t apr_pollcb_create ( apr_pollcb_t **  pollcb,
apr_uint32_t  size,
apr_pool_t p,
apr_uint32_t  flags 
)

Set up a pollcb object

Parameters:
pollcbThe pointer in which to return the newly created object
sizeThe maximum number of descriptors that a single _poll can return.
pThe pool from which to allocate the pollcb
flagsOptional flags to modify the operation of the pollcb.
Remarks:
If flags contains APR_POLLSET_WAKEABLE, then a pollcb is created with an additional internal pipe object used for the apr_pollcb_wakeup() call. The actual size of pollcb is in that case size + 1.
Pollcb is only supported on some platforms; the apr_pollcb_create() call will fail with APR_ENOTIMPL on platforms where it is not supported.
apr_status_t apr_pollcb_create_ex ( apr_pollcb_t **  pollcb,
apr_uint32_t  size,
apr_pool_t p,
apr_uint32_t  flags,
apr_pollset_method_e  method 
)

Set up a pollcb object

Parameters:
pollcbThe pointer in which to return the newly created object
sizeThe maximum number of descriptors that a single _poll can return.
pThe pool from which to allocate the pollcb
flagsOptional flags to modify the operation of the pollcb.
methodPoll method to use. See apr_pollset_method_e. If this method cannot be used, the default method will be used unless the APR_POLLSET_NODEFAULT flag has been specified.
Remarks:
If flags contains APR_POLLSET_WAKEABLE, then a pollcb is created with an additional internal pipe object used for the apr_pollcb_wakeup() call. The actual size of pollcb is in that case size + 1.
Pollcb is only supported on some platforms; the apr_pollcb_create_ex() call will fail with APR_ENOTIMPL on platforms where it is not supported.
const char* apr_pollcb_method_name ( apr_pollcb_t pollcb)

Return a printable representation of the pollcb method.

Parameters:
pollcbThe pollcb to use
apr_status_t apr_pollcb_poll ( apr_pollcb_t pollcb,
apr_interval_time_t  timeout,
apr_pollcb_cb_t  func,
void *  baton 
)

Block for activity on the descriptor(s) in a pollcb

Parameters:
pollcbThe pollcb to use
timeoutThe amount of time in microseconds to wait. This is a maximum, not a minimum. If a descriptor is signalled, the function will return before this time. If timeout is negative, the function will block until a descriptor is signalled or until apr_pollcb_wakeup() has been called.
funcCallback function to call for each active descriptor.
batonOpaque baton passed to the callback function.
Remarks:
Multiple signalled conditions for the same descriptor may be reported in one or more calls to the callback function, depending on the implementation.
APR_EINTR will be returned if the pollset has been created with APR_POLLSET_WAKEABLE and apr_pollcb_wakeup() has been called while waiting for activity.
apr_status_t apr_pollcb_remove ( apr_pollcb_t pollcb,
apr_pollfd_t descriptor 
)

Remove a descriptor from a pollcb

Parameters:
pollcbThe pollcb from which to remove the descriptor
descriptorThe descriptor to remove
Remarks:
If the descriptor is not found, APR_NOTFOUND is returned.
apr_pollcb_remove() cannot be used to remove a subset of requested events for a descriptor. The reqevents field in the apr_pollfd_t parameter must contain the same value when removing as when adding.
apr_status_t apr_pollcb_wakeup ( apr_pollcb_t pollcb)

Interrupt the blocked apr_pollcb_poll() call.

Parameters:
pollcbThe pollcb to use
Remarks:
If the pollcb was not created with APR_POLLSET_WAKEABLE the return value is APR_EINIT.
apr_status_t apr_pollset_add ( apr_pollset_t pollset,
const apr_pollfd_t descriptor 
)

Add a socket or file descriptor to a pollset

Parameters:
pollsetThe pollset to which to add the descriptor
descriptorThe descriptor to add
Remarks:
If you set client_data in the descriptor, that value will be returned in the client_data field whenever this descriptor is signalled in apr_pollset_poll().
If the pollset has been created with APR_POLLSET_THREADSAFE and thread T1 is blocked in a call to apr_pollset_poll() for this same pollset that is being modified via apr_pollset_add() in thread T2, the currently executing apr_pollset_poll() call in T1 will either: (1) automatically include the newly added descriptor in the set of descriptors it is watching or (2) return immediately with APR_EINTR. Option (1) is recommended, but option (2) is allowed for implementations where option (1) is impossible or impractical.
If the pollset has been created with APR_POLLSET_NOCOPY, the apr_pollfd_t structure referenced by descriptor will not be copied and must have a lifetime at least as long as the pollset.
Do not add the same socket or file descriptor to the same pollset multiple times, even if the requested events differ for the different calls to apr_pollset_add(). If the events of interest for a descriptor change, you must first remove the descriptor from the pollset with apr_pollset_remove(), then add it again specifying all requested events.
apr_status_t apr_pollset_create ( apr_pollset_t **  pollset,
apr_uint32_t  size,
apr_pool_t p,
apr_uint32_t  flags 
)

Set up a pollset object

Parameters:
pollsetThe pointer in which to return the newly created object
sizeThe maximum number of descriptors that this pollset can hold
pThe pool from which to allocate the pollset
flagsOptional flags to modify the operation of the pollset.
Remarks:
If flags contains APR_POLLSET_THREADSAFE, then a pollset is created on which it is safe to make concurrent calls to apr_pollset_add(), apr_pollset_remove() and apr_pollset_poll() from separate threads. This feature is only supported on some platforms; the apr_pollset_create() call will fail with APR_ENOTIMPL on platforms where it is not supported.
If flags contains APR_POLLSET_WAKEABLE, then a pollset is created with an additional internal pipe object used for the apr_pollset_wakeup() call. The actual size of pollset is in that case size + 1. This feature is only supported on some platforms; the apr_pollset_create() call will fail with APR_ENOTIMPL on platforms where it is not supported.
If flags contains APR_POLLSET_NOCOPY, then the apr_pollfd_t structures passed to apr_pollset_add() are not copied and must have a lifetime at least as long as the pollset.
Some poll methods (including APR_POLLSET_KQUEUE, APR_POLLSET_PORT, and APR_POLLSET_EPOLL) do not have a fixed limit on the size of the pollset. For these methods, the size parameter controls the maximum number of descriptors that will be returned by a single call to apr_pollset_poll().
apr_status_t apr_pollset_create_ex ( apr_pollset_t **  pollset,
apr_uint32_t  size,
apr_pool_t p,
apr_uint32_t  flags,
apr_pollset_method_e  method 
)

Set up a pollset object

Parameters:
pollsetThe pointer in which to return the newly created object
sizeThe maximum number of descriptors that this pollset can hold
pThe pool from which to allocate the pollset
flagsOptional flags to modify the operation of the pollset.
methodPoll method to use. See apr_pollset_method_e. If this method cannot be used, the default method will be used unless the APR_POLLSET_NODEFAULT flag has been specified.
Remarks:
If flags contains APR_POLLSET_THREADSAFE, then a pollset is created on which it is safe to make concurrent calls to apr_pollset_add(), apr_pollset_remove() and apr_pollset_poll() from separate threads. This feature is only supported on some platforms; the apr_pollset_create_ex() call will fail with APR_ENOTIMPL on platforms where it is not supported.
If flags contains APR_POLLSET_WAKEABLE, then a pollset is created with additional internal pipe object used for the apr_pollset_wakeup() call. The actual size of pollset is in that case size + 1. This feature is only supported on some platforms; the apr_pollset_create_ex() call will fail with APR_ENOTIMPL on platforms where it is not supported.
If flags contains APR_POLLSET_NOCOPY, then the apr_pollfd_t structures passed to apr_pollset_add() are not copied and must have a lifetime at least as long as the pollset.
Some poll methods (including APR_POLLSET_KQUEUE, APR_POLLSET_PORT, and APR_POLLSET_EPOLL) do not have a fixed limit on the size of the pollset. For these methods, the size parameter controls the maximum number of descriptors that will be returned by a single call to apr_pollset_poll().
apr_status_t apr_pollset_destroy ( apr_pollset_t pollset)

Destroy a pollset object

Parameters:
pollsetThe pollset to destroy
const char* apr_pollset_method_name ( apr_pollset_t pollset)

Return a printable representation of the pollset method.

Parameters:
pollsetThe pollset to use
apr_status_t apr_pollset_poll ( apr_pollset_t pollset,
apr_interval_time_t  timeout,
apr_int32_t *  num,
const apr_pollfd_t **  descriptors 
)

Block for activity on the descriptor(s) in a pollset

Parameters:
pollsetThe pollset to use
timeoutThe amount of time in microseconds to wait. This is a maximum, not a minimum. If a descriptor is signalled, the function will return before this time. If timeout is negative, the function will block until a descriptor is signalled or until apr_pollset_wakeup() has been called.
numNumber of signalled descriptors (output parameter)
descriptorsArray of signalled descriptors (output parameter)
Remarks:
APR_EINTR will be returned if the pollset has been created with APR_POLLSET_WAKEABLE, apr_pollset_wakeup() has been called while waiting for activity, and there were no signalled descriptors at the time of the wakeup call.
Multiple signalled conditions for the same descriptor may be reported in one or more returned apr_pollfd_t structures, depending on the implementation.
apr_status_t apr_pollset_remove ( apr_pollset_t pollset,
const apr_pollfd_t descriptor 
)

Remove a descriptor from a pollset

Parameters:
pollsetThe pollset from which to remove the descriptor
descriptorThe descriptor to remove
Remarks:
If the descriptor is not found, APR_NOTFOUND is returned.
If the pollset has been created with APR_POLLSET_THREADSAFE and thread T1 is blocked in a call to apr_pollset_poll() for this same pollset that is being modified via apr_pollset_remove() in thread T2, the currently executing apr_pollset_poll() call in T1 will either: (1) automatically exclude the newly added descriptor in the set of descriptors it is watching or (2) return immediately with APR_EINTR. Option (1) is recommended, but option (2) is allowed for implementations where option (1) is impossible or impractical.
apr_pollset_remove() cannot be used to remove a subset of requested events for a descriptor. The reqevents field in the apr_pollfd_t parameter must contain the same value when removing as when adding.
apr_status_t apr_pollset_wakeup ( apr_pollset_t pollset)

Interrupt the blocked apr_pollset_poll() call.

Parameters:
pollsetThe pollset to use
Remarks:
If the pollset was not created with APR_POLLSET_WAKEABLE the return value is APR_EINIT.
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