# ACE_Message_Block Class Reference

Stores messages for use throughout ACE (particularly in an ACE_Message_Queue). More...

`#include <Message_Block.h>`

Collaboration diagram for ACE_Message_Block:

[legend]
List of all members.

## Public Types

typedef int | ACE_Message_Type
typedef unsigned long | Message_Flags
enum | { MB_DATA = 0x01, MB_PROTO = 0x02, MB_BREAK = 0x03, MB_PASSFP = 0x04, MB_EVENT = 0x05, MB_SIG = 0x06, MB_IOCTL = 0x07, MB_SETOPTS = 0x08, MB_IOCACK = 0x81, MB_IOCNAK = 0x82, MB_PCPROTO = 0x83, MB_PCSIG = 0x84, MB_READ = 0x85, MB_FLUSH = 0x86, MB_STOP = 0x87, MB_START = 0x88, MB_HANGUP = 0x89, MB_ERROR = 0x8a, MB_PCEVENT = 0x8b, MB_NORMAL = 0x00, MB_PRIORITY = 0x80, MB_USER = 0x200 }
enum | { DONT_DELETE = 01, USER_FLAGS = 0x1000 }

## Public Member Functions

| ACE_Message_Block (ACE_Allocator *message_block_allocator=0)
| Create an empty message.
| ACE_Message_Block (ACE_Data_Block *, Message_Flags flags=0, ACE_Allocator *message_block_allocator=0)
| ACE_Message_Block (const char *data, size_t size=0, unsigned long priority=ACE_DEFAULT_MESSAGE_BLOCK_PRIORITY)

ACE_Message_Block (size_t size, ACE_Message_Type type=MB_DATA, ACE_Message_Block *cont=0, const char *data=0, ACE_Allocator *allocator_strategy=0, ACE_Lock *locking_strategy=0, unsigned long priority=ACE_DEFAULT_MESSAGE_BLOCK_PRIORITY, const ACE_Time_Value &execution_time=ACE_Time_Value::zero, const ACE_Time_Value &deadline_time=ACE_Time_Value::max_time, ACE_Allocator *data_block_allocator=0, ACE_Allocator *message_block_allocator=0)

| ACE_Message_Block (const ACE_Message_Block &mb, size_t align)
int | init (const char *data, size_t size=0)

int

init (size_t size, ACE_Message_Type type=MB_DATA, ACE_Message_Block *cont=0, const char *data=0, ACE_Allocator *allocator_strategy=0, ACE_Lock *locking_strategy=0, unsigned long priority=ACE_DEFAULT_MESSAGE_BLOCK_PRIORITY, const ACE_Time_Value &execution_time=ACE_Time_Value::zero, const ACE_Time_Value &deadline_time=ACE_Time_Value::max_time, ACE_Allocator *data_block_allocator=0, ACE_Allocator *message_block_allocator=0)

virtual | ~ACE_Message_Block (void)
ACE_Message_Type | msg_type (void) const
| Get type of the message.
void | msg_type (ACE_Message_Type type)
| Set type of the message.
int | is_data_msg (void) const
| Find out what type of message this is.
ACE_Message_Type | msg_class (void) const
Message_Flags | set_flags (Message_Flags more_flags)
Message_Flags | clr_flags (Message_Flags less_flags)
Message_Flags | flags (void) const
| Get the current message flags.
Message_Flags | set_self_flags (ACE_Message_Block::Message_Flags more_flags)
Message_Flags | clr_self_flags (ACE_Message_Block::Message_Flags less_flags)
Message_Flags | self_flags (void) const
| Get the current message flags.
unsigned long | msg_priority (void) const
| Get priority of the message.
void | msg_priority (unsigned long priority)
| Set priority of the message.
const ACE_Time_Value & | msg_execution_time (void) const
| Get execution time associated with the message.
void | msg_execution_time (const ACE_Time_Value &et)
| Set execution time associated with the message.
const ACE_Time_Value & | msg_deadline_time (void) const
| Get absolute time of deadline associated with the message.
void | msg_deadline_time (const ACE_Time_Value &dt)
| Set absolute time of deadline associated with the message.
virtual ACE_Message_Block * | clone (Message_Flags mask=0) const
virtual ACE_Message_Block * | duplicate (void) const
| Return a "shallow" copy that increments our reference count by 1.
virtual ACE_Message_Block * | release (void)
int | copy (const char *buf, size_t n)
int | copy (const char *buf)
int | crunch (void)
void | reset (void)
void | access_allocators (ACE_Allocator *&allocator_strategy, ACE_Allocator *&data_block_allocator, ACE_Allocator *&message_block_allocator)
void | reset_allocators (ACE_Allocator *allocator_strategy=0, ACE_Allocator *data_block_allocator=0, ACE_Allocator *message_block_allocator=0)
char * | base (void) const
| Get message data.
void | base (char *data, size_t size, Message_Flags=DONT_DELETE)
| Set message data (doesn't reallocate).
char * | end (void) const
| Return a pointer to 1 past the end of the allocated data in a message.
char * | mark (void) const
char * | rd_ptr (void) const
| Get the read pointer.
void | rd_ptr (char *ptr)
| Set the read pointer to <ptr>.
void | rd_ptr (size_t n)
| Set the read pointer ahead <n> bytes.
char * | wr_ptr (void) const
| Get the write pointer.
void | wr_ptr (char *ptr)
| Set the write pointer to <ptr>.
void | wr_ptr (size_t n)
ACE_Data_Block * | data_block (void) const
void | data_block (ACE_Data_Block *)
ACE_Data_Block * | replace_data_block (ACE_Data_Block *)
ACE_Message_Block * | cont (void) const
| Get the continuation field.
void | cont (ACE_Message_Block *)
| Set the continuation field.
ACE_Message_Block * | next (void) const
| Get link to next message.
void | next (ACE_Message_Block *)
| Set link to next message.
ACE_Message_Block * | prev (void) const
| Get link to prev message.
void | prev (ACE_Message_Block *)
| Set link to prev message.
ACE_Lock * | locking_strategy (void)
| Get the locking strategy.
ACE_Lock * | locking_strategy (ACE_Lock *)
| Set a new locking strategy and return the hold one.
int | reference_count (void) const
| Get the current reference count.
void | dump (void) const
| Dump the state of an object.
Message length and size operations
Message length is (wr_ptr - rd_ptr). Message size is capacity of the message, including data outside the [rd_ptr,wr_ptr] range.
size_t | length (void) const
| Get the length of the message.
void | length (size_t n)
| Set the length of the message.
size_t | total_length (void) const
size_t | total_size (void) const
void | total_size_and_length (size_t &mb_size, size_t &mb_length) const
size_t | size (void) const
int | size (size_t length)
size_t | total_capacity (void) const
size_t | capacity (void) const
| Get the number of allocated bytes in the top-level <message_block>.
size_t | space (void) const

## Static Public Member Functions

ACE_Message_Block * | duplicate (const ACE_Message_Block *mb)
ACE_Message_Block * | release (ACE_Message_Block *mb)

## Public Attributes

| ACE_ALLOC_HOOK_DECLARE
| Declare the dynamic allocation hooks.

## Protected Member Functions

| ACE_Message_Block (size_t size, ACE_Message_Type type, ACE_Message_Block *cont, const char *data, ACE_Allocator *allocator_strategy, ACE_Lock *locking_strategy, Message_Flags flags, unsigned long priority, const ACE_Time_Value &execution_time, const ACE_Time_Value &deadline_time, ACE_Data_Block *db, ACE_Allocator *data_block_allocator, ACE_Allocator *message_block_allocator)
| Perform the actual initialization.
int | release_i (ACE_Lock *lock)
int | init_i (size_t size, ACE_Message_Type type, ACE_Message_Block *cont, const char *data, ACE_Allocator *allocator_strategy, ACE_Lock *locking_strategy, Message_Flags flags, unsigned long priority, const ACE_Time_Value &execution_time, const ACE_Time_Value &deadline_time, ACE_Data_Block *db, ACE_Allocator *data_block_allocator, ACE_Allocator *message_block_allocator)
| Perform the actual initialization.

## Protected Attributes

size_t | rd_ptr_
| Pointer to beginning of next read.
size_t | wr_ptr_
| Pointer to beginning of next write.
unsigned long | priority_
| Priority of message.
ACE_Message_Block * | cont_
| Pointer to next message block in the chain.
ACE_Message_Block * | next_
| Pointer to next message in the list.
ACE_Message_Block * | prev_
| Pointer to previous message in the list.
ACE_Message_Block::Message_Flags | flags_
| Misc flags (e.g., DONT_DELETE and USER_FLAGS).
ACE_Data_Block * | data_block_
ACE_Allocator * | message_block_allocator_

## Private Member Functions

ACE_Message_Block & | operator= (const ACE_Message_Block &)
| ACE_Message_Block (const ACE_Message_Block &)

## Friends

class | ACE_Data_Block

## Detailed Description

Stores messages for use throughout ACE (particularly in an ACE_Message_Queue).

An ACE_Message_Block is modeled after the message data structures used in System V STREAMS. Its purpose is to enable efficient manipulation of arbitrarily large messages without incurring much memory copying overhead. Here are the main characteristics of an ACE_Message_Block:

- Contains a pointer to a reference-counted ACE_Data_Block, which in turn points to the actual data buffer. This allows very flexible and efficient sharing of data by multiple ACE_Message_Block objects.
- One or more ACE_Message_Blocks can be linked to form a ``fragment chain.''
- ACE_Message_Blocks can be linked together in a doubly linked fashion to form a queue of messages (this is how ACE_Message_Queue works).

See also:
  C++NPv1, section 4.2; APG, section 12.3.2.

## Member Typedef Documentation

typedef int ACE_Message_Block::ACE_Message_Type

typedef unsigned long ACE_Message_Block::Message_Flags

## Member Enumeration Documentation

anonymous enum

Enumeration values:

  MB_DATA | Undifferentiated data message.
  MB_PROTO | Undifferentiated protocol control.
  MB_BREAK | Line break (regular and priority).
  MB_PASSFP | Pass file pointer.
  MB_EVENT | Post an event to an event queue.
  MB_SIG | Generate process signal.
  MB_IOCTL | ioctl; set/get params
  MB_SETOPTS | Set various stream head options.
  MB_IOCACK | Acknowledge ioctl (high priority; go to head of queue).
  MB_IOCNAK | Negative ioctl acknowledge.
  MB_PCPROTO | Priority proto message.
  MB_PCSIG | Generate process signal.
  MB_READ | Generate read notification.
  MB_FLUSH | Flush your queues.
  MB_STOP | Stop transmission immediately.
  MB_START | Restart transmission after stop.
  MB_HANGUP | Line disconnect.
  MB_ERROR | Fatal error used to set u.u_error.
  MB_PCEVENT | Post an event to an event queue.
  MB_NORMAL | Normal priority message mask.
  MB_PRIORITY | High priority control message mask.
  MB_USER | User-defined message mask.

anonymous enum

Enumeration values:

  DONT_DELETE | Don't delete the data on exit since we don't own it.
  USER_FLAGS | user defined flags start here

## Constructor & Destructor Documentation

ACE_Message_Block::ACE_Message_Block | ( | ACE_Allocator * | message_block_allocator = `0` | ) |

| Create an empty message.

ACE_Message_Block::ACE_Message_Block | ( | ACE_Data_Block * | ,
|  | Message_Flags | flags = `0`,
|  | ACE_Allocator * | message_block_allocator = `0`
| ) |

| Create an ACE_Message_Block that owns the specified ACE_Data_Block without copying it. If the flags is set to `DONT_DELETE` we don't delete the ACE_Data_Block. It is left to the client's responsibility to take care of the memory allocated for the data_block

ACE_Message_Block::ACE_Message_Block | ( | const char * | data,
|  | size_t | size = `0`,
|  | unsigned long | priority = `ACE_DEFAULT_MESSAGE_BLOCK_PRIORITY`
| ) |

| Create an ACE_Message_Block that refers to data without copying it. The data memory will not be freed when this block is destroyed; memory management of data is left to the caller. Note that the `size` of the new ACE_Message_Block will be size, but the `length` will be 0 until the write pointer is changed.

ACE_Message_Block::ACE_Message_Block | ( | size_t | size,
|  | ACE_Message_Type | type = `MB_DATA`,
|  | ACE_Message_Block * | cont = `0`,
|  | const char * | data = `0`,
|  | ACE_Allocator * | allocator_strategy = `0`,
|  | ACE_Lock * | locking_strategy = `0`,
|  | unsigned long | priority = `ACE_DEFAULT_MESSAGE_BLOCK_PRIORITY`,
|  | const ACE_Time_Value & | execution_time = `ACE_Time_Value::zero`,
|  | const ACE_Time_Value & | deadline_time = `ACE_Time_Value::max_time`,
|  | ACE_Allocator * | data_block_allocator = `0`,
|  | ACE_Allocator * | message_block_allocator = `0`
| ) |

Create an initialized message of type type containing size bytes. The cont argument initializes the continuation field in the ACE_Message_Block. If data == 0 then this block allocates and owns the block's memory, using allocator to get the data if it's non-0. If data != 0 then this block refers to that memory until this this block ceases to exist; this object will not free data on destruction. If locking_strategy is non-0 then this is used to protect regions of code that access shared state (e.g., reference counting) from race conditions. Note that the `size` of the ACE_Message_Block will be size, but the `length` will be 0 until the write pointer is set. The data_block_allocator is used to allocate the data blocks while the allocator_strategy is used to allocate the buffers contained by those. The message_block_allocator is used to allocate new ACE_Message_Block objects when the duplicate() method is called. If a message_block_allocator is given, this ACE_Message_Block and future ACE_Message_Block objects created by duplicate() will be freed using this allocator when they are released.

Note:
  If you use this allocator, the ACE_Message_Block you created should have been created using this allocator because it will be released to the same allocator.

ACE_Message_Block::ACE_Message_Block | ( | const ACE_Message_Block & | mb,
|  | size_t | align
| ) |

A copy constructor. This constructor is a bit different. If the incoming Message Block has a data block from the stack this constructor does a deep copy ie. allocates a new data block on the heap and does a copy of the data from the incoming message block. As a final note, the alignment information is used to align the data block if it is created afresh. If the incoming <mb> has a data block has a data block allocated from the heap, then this constructor just duplicates (ie. a shallow copy) the data block of the incoming <mb>.

ACE_Message_Block::~ACE_Message_Block | ( | void |  | ) | `[virtual]`

| Delete all the resources held in the message. Note that <release()> is designed to release the continuation chain; the destructor is not. See <release()> for details.

ACE_Message_Block::ACE_Message_Block | ( | size_t | size,
|  | ACE_Message_Type | type,
|  | ACE_Message_Block * | cont,
|  | const char * | data,
|  | ACE_Allocator * | allocator_strategy,
|  | ACE_Lock * | locking_strategy,
|  | Message_Flags | flags,
|  | unsigned long | priority,
|  | const ACE_Time_Value & | execution_time,
|  | const ACE_Time_Value & | deadline_time,
|  | ACE_Data_Block * | db,
|  | ACE_Allocator * | data_block_allocator,
|  | ACE_Allocator * | message_block_allocator
| ) | `[protected]`

| Perform the actual initialization.

ACE_Message_Block::ACE_Message_Block | ( | const ACE_Message_Block & |  | ) | `[private]`

## Member Function Documentation

ACE_INLINE void ACE_Message_Block::access_allocators | ( | ACE_Allocator *& | allocator_strategy,
|  | ACE_Allocator *& | data_block_allocator,
|  | ACE_Allocator *& | message_block_allocator
| ) |

This method returns the allocators only from the first message block in the chain.

Parameters:

  | allocator_strategy | Strategy used to allocate the underlying buffer
  | data_block_allocator | Strategy used to allocate the underlying data block
  | message_block_allocator | Strategy used to allocate the message block

ACE_INLINE void ACE_Message_Block::base | ( | char * | data,
|  | size_t | size,
|  | Message_Flags | = `DONT_DELETE`
| ) |

| Set message data (doesn't reallocate).

ACE_INLINE char * ACE_Message_Block::base | ( | void |  | ) | const

| Get message data.

ACE_INLINE size_t ACE_Message_Block::capacity | ( | void |  | ) | const

| Get the number of allocated bytes in the top-level <message_block>.

ACE_Message_Block * ACE_Message_Block::clone | ( | Message_Flags | mask = `0` | ) | const`[virtual]`

| Return an exact "deep copy" of the message, i.e., create fresh new copies of all the Data_Blocks and continuations.

ACE_INLINE ACE_Message_Block::Message_Flags ACE_Message_Block::clr_flags | ( | Message_Flags | less_flags | ) |

| Clear the message flag bits specified in <less_flags> and return the new value.

ACE_INLINE ACE_Message_Block::Message_Flags ACE_Message_Block::clr_self_flags | ( | ACE_Message_Block::Message_Flags | less_flags | ) |

| Clear the message flag bits specified in <less_flags> and return the new value.

ACE_INLINE void ACE_Message_Block::cont | ( | ACE_Message_Block * |  | ) |

| Set the continuation field.

ACE_INLINE ACE_Message_Block * ACE_Message_Block::cont | ( | void |  | ) | const

| Get the continuation field.

int ACE_Message_Block::copy | ( | const char * | buf | ) |

Copies a 0-terminated character string into this ACE_Message_Block. The string is copied into the block starting at the current write pointer. The 0-terminator is included in the copied data.

Parameters:

  | buf | Pointer to the character string to copy from.

Return values:

  | 0 | on success; the write pointer is advanced by the string's length, including the 0 terminator.
  | -1 | if the amount of free space following the write pointer in the block is less than required to hold the entire string. Free space can be checked by calling space().

int ACE_Message_Block::copy | ( | const char * | buf,
|  | size_t | n
| ) |

Copies data into this ACE_Message_Block. Data is copied into the block starting at the current write pointer.

Parameters:

  | buf | Pointer to the buffer to copy from.
  | n | The number of bytes to copy.

Return values:

  0

  on success; the write pointer is advanced by
  - n.

  -1

  if the amount of free space following the write pointer in the block is less than
  - n. Free space can be checked by calling space().

int ACE_Message_Block::crunch | ( | void |  | ) |

| Normalizes data in the top-level <message_block> to align with the base, i.e., it "shifts" the data pointed to by <rd_ptr> down to the <base> and then readjusts <rt_ptr> to point to <base> and <wr_ptr> to point to <base> + the length of the moved data. Returns -1 and does nothing if the <rd_ptr> is > <wr_ptr>, else 0 on success.

ACE_BEGIN_VERSIONED_NAMESPACE_DECL void ACE_Message_Block::data_block | ( | ACE_Data_Block * |  | ) |

| Set a new data block pointer. The original ACE_Data_Block is released as a result of this call. If you need to keep the original block, call <replace_data_block> instead. Upon return, this ACE_Message_Block holds a pointer to the new ACE_Data_Block, taking over the reference you held on it prior to the call.

ACE_BEGIN_VERSIONED_NAMESPACE_DECL ACE_INLINE ACE_Data_Block * ACE_Message_Block::data_block | ( | void |  | ) | const

| Get a pointer to the data block. Note that the ACE_Message_Block still references the block; this call does not change the reference count.

void ACE_Message_Block::dump | ( | void |  | ) | const

| Dump the state of an object.

ACE_Message_Block * ACE_Message_Block::duplicate | ( | const ACE_Message_Block * | mb | ) | `[static]`

| Return a "shallow" copy that increments our reference count by 1. This is similar to CORBA's <_duplicate> method, which is useful if you want to eliminate lots of checks for NULL <mb> pointers before calling <_duplicate> on them.

ACE_Message_Block * ACE_Message_Block::duplicate | ( | void |  | ) | const`[virtual]`

| Return a "shallow" copy that increments our reference count by 1.

ACE_INLINE char * ACE_Message_Block::end | ( | void |  | ) | const

| Return a pointer to 1 past the end of the allocated data in a message.

ACE_INLINE ACE_Message_Block::Message_Flags ACE_Message_Block::flags | ( | void |  | ) | const

| Get the current message flags.

int ACE_Message_Block::init | ( | size_t | size,
|  | ACE_Message_Type | type = `MB_DATA`,
|  | ACE_Message_Block * | cont = `0`,
|  | const char * | data = `0`,
|  | ACE_Allocator * | allocator_strategy = `0`,
|  | ACE_Lock * | locking_strategy = `0`,
|  | unsigned long | priority = `ACE_DEFAULT_MESSAGE_BLOCK_PRIORITY`,
|  | const ACE_Time_Value & | execution_time = `ACE_Time_Value::zero`,
|  | const ACE_Time_Value & | deadline_time = `ACE_Time_Value::max_time`,
|  | ACE_Allocator * | data_block_allocator = `0`,
|  | ACE_Allocator * | message_block_allocator = `0`
| ) |

Create an initialized message of type <type> containing <size> bytes. The <cont> argument initializes the continuation field in the <message_block>. If <data> == 0 then we create and own the <data>, using <allocator> to get the data if it's non-0. If <data> != 0 we assume that we have ownership of the <data> till this object ceases to exist (and don't delete it during destruction). If <locking_strategy> is non-0 then this is used to protect regions of code that access shared state (e.g., reference counting) from race conditions. Note that the <size> of the <message_block> will be <size>, but the <length> will be 0 until <wr_ptr> is set. The <data_block_allocator> is use to allocate the data blocks while the <allocator_strategy> is used to allocate the buffers contained by those.

int ACE_Message_Block::init | ( | const char * | data,
|  | size_t | size = `0`
| ) |

| Create a Message Block that assumes it has ownership of <data>, but in reality it doesnt (i.e., cannot delete it since it didn't malloc it!). Note that the <size> of the <message_block> will be <size>, but the <length> will be 0 until <wr_ptr> is set.

int ACE_Message_Block::init_i | ( | size_t | size,
|  | ACE_Message_Type | type,
|  | ACE_Message_Block * | cont,
|  | const char * | data,
|  | ACE_Allocator * | allocator_strategy,
|  | ACE_Lock * | locking_strategy,
|  | Message_Flags | flags,
|  | unsigned long | priority,
|  | const ACE_Time_Value & | execution_time,
|  | const ACE_Time_Value & | deadline_time,
|  | ACE_Data_Block * | db,
|  | ACE_Allocator * | data_block_allocator,
|  | ACE_Allocator * | message_block_allocator
| ) | `[protected]`

| Perform the actual initialization.

ACE_INLINE int ACE_Message_Block::is_data_msg | ( | void |  | ) | const

| Find out what type of message this is.

ACE_INLINE void ACE_Message_Block::length | ( | size_t | n | ) |

| Set the length of the message.

ACE_INLINE size_t ACE_Message_Block::length | ( | void |  | ) | const

| Get the length of the message.

ACE_INLINE ACE_Lock * ACE_Message_Block::locking_strategy | ( | ACE_Lock * |  | ) |

| Set a new locking strategy and return the hold one.

ACE_INLINE ACE_Lock * ACE_Message_Block::locking_strategy | ( | void |  | ) |

| Get the locking strategy.

ACE_INLINE char * ACE_Message_Block::mark | ( | void |  | ) | const

| Return a pointer to 1 past the end of the allotted data in a message. Allotted data may be less than allocated data if a value smaller than capacity() to is passed to size().

ACE_INLINE ACE_Message_Block::ACE_Message_Type ACE_Message_Block::msg_class | ( | void |  | ) | const

| Find out what class of message this is (there are two classes, <normal> messages and <high-priority> messages).

ACE_INLINE void ACE_Message_Block::msg_deadline_time | ( | const ACE_Time_Value & | dt | ) |

| Set absolute time of deadline associated with the message.

ACE_INLINE const ACE_Time_Value & ACE_Message_Block::msg_deadline_time | ( | void |  | ) | const

| Get absolute time of deadline associated with the message.

ACE_INLINE void ACE_Message_Block::msg_execution_time | ( | const ACE_Time_Value & | et | ) |

| Set execution time associated with the message.

ACE_INLINE const ACE_Time_Value & ACE_Message_Block::msg_execution_time | ( | void |  | ) | const

| Get execution time associated with the message.

ACE_INLINE void ACE_Message_Block::msg_priority | ( | unsigned long | priority | ) |

| Set priority of the message.

ACE_INLINE unsigned long ACE_Message_Block::msg_priority | ( | void |  | ) | const

| Get priority of the message.

ACE_INLINE void ACE_Message_Block::msg_type | ( | ACE_Message_Type | type | ) |

| Set type of the message.

ACE_INLINE ACE_Message_Block::ACE_Message_Type ACE_Message_Block::msg_type | ( | void |  | ) | const

| Get type of the message.

ACE_INLINE void ACE_Message_Block::next | ( | ACE_Message_Block * |  | ) |

| Set link to next message.

ACE_INLINE ACE_Message_Block * ACE_Message_Block::next | ( | void |  | ) | const

| Get link to next message.

ACE_Message_Block & ACE_Message_Block::operator= | ( | const ACE_Message_Block & |  | ) | `[private]`

ACE_INLINE void ACE_Message_Block::prev | ( | ACE_Message_Block * |  | ) |

| Set link to prev message.

ACE_INLINE ACE_Message_Block * ACE_Message_Block::prev | ( | void |  | ) | const

| Get link to prev message.

ACE_INLINE void ACE_Message_Block::rd_ptr | ( | size_t | n | ) |

| Set the read pointer ahead <n> bytes.

ACE_INLINE void ACE_Message_Block::rd_ptr | ( | char * | ptr | ) |

| Set the read pointer to <ptr>.

ACE_INLINE char * ACE_Message_Block::rd_ptr | ( | void |  | ) | const

| Get the read pointer.

ACE_INLINE int ACE_Message_Block::reference_count | ( | void |  | ) | const

| Get the current reference count.

ACE_Message_Block * ACE_Message_Block::release | ( | ACE_Message_Block * | mb | ) | `[static]`

| This behaves like the non-static method <release>, except that it checks if <mb> is 0. This is similar to <CORBA::release>, which is useful if you want to eliminate lots of checks for NULL pointers before calling <release> on them. Returns <mb>.

ACE_Message_Block * ACE_Message_Block::release | ( | void |  | ) | `[virtual]`

Decrease the shared ACE_Data_Block's reference count by 1. If the ACE_Data_Block's reference count goes to 0, it is deleted. In all cases, this ACE_Message_Block is deleted - it must have come from the heap, or there will be trouble.

release() is designed to release the continuation chain; the destructor is not. If we make the destructor release the continuation chain by calling release() or delete on the message blocks in the continuation chain, the following code will not work since the message block in the continuation chain is not off the heap:

ACE_Message_Block mb1 (1024); ACE_Message_Block mb2 (1024);

mb1.cont (&mb2);

And hence, call release() on a dynamically allocated message block. This will release all the message blocks in the continuation chain. If you call delete or let the message block fall off the stack, cleanup of the message blocks in the continuation chain becomes the responsibility of the user.

Return values:

  | 0,always,and | the object this method was invoked on is no longer valid.

int ACE_Message_Block::release_i | ( | ACE_Lock * | lock | ) | `[protected]`

| Internal release implementation Returns 1 if the data block has to be destroyed.

ACE_INLINE ACE_Data_Block * ACE_Message_Block::replace_data_block | ( | ACE_Data_Block * |  | ) |

| Set a new data block pointer. A pointer to the original ACE_Data_Block is returned, and not released (as it is with <data_block>).

ACE_INLINE void ACE_Message_Block::reset | ( | void |  | ) |

| Resets the Message Block data to contain nothing, i.e., sets the read and write pointers to align with the base.

ACE_INLINE void ACE_Message_Block::reset_allocators | ( | ACE_Allocator * | allocator_strategy = `0`,
|  | ACE_Allocator * | data_block_allocator = `0`,
|  | ACE_Allocator * | message_block_allocator = `0`
| ) |

| This method resets the allocators in all the message blocks in the chain.

ACE_INLINE ACE_Message_Block::Message_Flags ACE_Message_Block::self_flags | ( | void |  | ) | const

| Get the current message flags.

ACE_INLINE ACE_Message_Block::Message_Flags ACE_Message_Block::set_flags | ( | Message_Flags | more_flags | ) |

| Bitwise-or the <more_flags> into the existing message flags and return the new value.

ACE_INLINE ACE_Message_Block::Message_Flags ACE_Message_Block::set_self_flags | ( | ACE_Message_Block::Message_Flags | more_flags | ) |

| Bitwise-or the <more_flags> into the existing message flags and return the new value.

int ACE_Message_Block::size | ( | size_t | length | ) |

| Set the number of bytes in the top-level <message_block>, reallocating space if necessary. However, the <rd_ptr_> and <wr_ptr_> remain at the original offsets into the buffer, even if it is reallocated. Returns 0 if successful, else -1.

ACE_INLINE size_t ACE_Message_Block::size | ( | void |  | ) | const

| Get the number of bytes in the top-level <message_block> (i.e., does not consider the bytes in chained <message_block>s).

ACE_INLINE size_t ACE_Message_Block::space | ( | void |  | ) | const

| Get the number of bytes available after the <wr_ptr_> in the top-level <message_block>.

size_t ACE_Message_Block::total_capacity | ( | void |  | ) | const

| Get the number of allocated bytes in all <message_block>, including chained <message_block>s.

size_t ACE_Message_Block::total_length | ( | void |  | ) | const

| Get the length of the <message_block>s, including chained <message_block>s.

size_t ACE_Message_Block::total_size | ( | void |  | ) | const

| Get the total number of bytes in all <message_block>s, including chained <message_block>s.

void ACE_Message_Block::total_size_and_length | ( | size_t & | mb_size,
|  | size_t & | mb_length
| ) | const

| Get the total number of bytes and total length in all <message_block>s, including chained <message_block>s.

ACE_INLINE void ACE_Message_Block::wr_ptr | ( | size_t | n | ) |

| Set the write pointer ahead <n> bytes. This is used to compute the <length> of a message.

ACE_INLINE void ACE_Message_Block::wr_ptr | ( | char * | ptr | ) |

| Set the write pointer to <ptr>.

ACE_INLINE char * ACE_Message_Block::wr_ptr | ( | void |  | ) | const

| Get the write pointer.

## Friends And Related Function Documentation

friend class ACE_Data_Block`[friend]`

## Member Data Documentation

ACE_Message_Block::ACE_ALLOC_HOOK_DECLARE

| Declare the dynamic allocation hooks.

ACE_Message_Block* ACE_Message_Block::cont_`[protected]`

| Pointer to next message block in the chain.

ACE_Data_Block* ACE_Message_Block::data_block_`[protected]`

| Pointer to the reference counted data structure that contains the actual memory buffer.

ACE_Message_Block::Message_Flags ACE_Message_Block::flags_`[protected]`

| Misc flags (e.g., DONT_DELETE and USER_FLAGS).

ACE_Allocator* ACE_Message_Block::message_block_allocator_`[protected]`

| The allocator used to destroy ourselves when release is called and create new message blocks on duplicate.

ACE_Message_Block* ACE_Message_Block::next_`[protected]`

| Pointer to next message in the list.

ACE_Message_Block* ACE_Message_Block::prev_`[protected]`

| Pointer to previous message in the list.

unsigned long ACE_Message_Block::priority_`[protected]`

| Priority of message.

size_t ACE_Message_Block::rd_ptr_`[protected]`

| Pointer to beginning of next read.

size_t ACE_Message_Block::wr_ptr_`[protected]`

| Pointer to beginning of next write.

The documentation for this class was generated from the following files:

- Message_Block.h
- Message_Block.cpp
- Message_Block.inl