#include <SV_Semaphore_Complex.h>
Public Types | |
enum | { ACE_CREATE = IPC_CREAT, ACE_OPEN = 0 } |
Public Member Functions | |
ACE_SV_Semaphore_Complex (void) | |
ACE_SV_Semaphore_Complex (key_t key, short create=ACE_SV_Semaphore_Complex::ACE_CREATE, int initial_value=1, u_short nsems=1, mode_t perms=ACE_DEFAULT_FILE_PERMS) | |
ACE_SV_Semaphore_Complex (const char *name, short create=ACE_SV_Semaphore_Complex::ACE_CREATE, int initial_value=1, u_short nsems=1, mode_t perms=ACE_DEFAULT_FILE_PERMS) | |
~ACE_SV_Semaphore_Complex (void) | |
int | open (const char *name, short flags=ACE_SV_Semaphore_Simple::ACE_CREATE, int initial_value=1, u_short nsems=1, mode_t perms=ACE_DEFAULT_FILE_PERMS) |
int | open (key_t key, short flags=ACE_SV_Semaphore_Simple::ACE_CREATE, int initial_value=1, u_short nsems=1, mode_t perms=ACE_DEFAULT_FILE_PERMS) |
int | close (void) |
int | acquire (u_short n=0, short flags=0) const |
Acquire the semaphore. | |
int | acquire_read (u_short n=0, short flags=0) const |
Acquire a semaphore for reading. | |
int | acquire_write (u_short n=0, short flags=0) const |
Acquire a semaphore for writing. | |
int | tryacquire (u_short n=0, short flags=0) const |
Try to acquire the semaphore. | |
int | tryacquire_read (u_short n=0, short flags=0) const |
Try to acquire the semaphore for reading. | |
int | tryacquire_write (u_short n=0, short flags=0) const |
Try to acquire the semaphore for writing. | |
int | release (u_short n=0, short flags=0) const |
Release the semaphore. | |
int | op (short val, u_short n=0, short flags=0) const |
int | op (sembuf op_vec[], u_short n) const |
General ACE_SV_Semaphore operation on an array of SV_Semaphores. | |
int | control (int cmd, semun arg, u_short n=0) const |
int | control (int cmd, int value=0, u_short n=0) const |
void | dump (void) const |
Dump the state of an object. | |
Public Attributes | |
ACE_ALLOC_HOOK_DECLARE | |
Declare the dynamic allocation hooks. | |
Static Private Attributes | |
static const int | BIGCOUNT_ = 10000 |
static sembuf | op_lock_ [2] |
static sembuf | op_endcreate_ [2] |
static sembuf | op_open_ [1] |
static sembuf | op_close_ [3] |
static sembuf | op_unlock_ [1] |
This code is a port to C++, inspired by: W. Richard Stevens from his book: UNIX Network Programming (Prentice Hall, ISBN 0-13-949876-1 - 1990). We provide a simpler and easier to understand interface to the System V Semaphore system calls. We create and use a 2 + n-member set for the requested <ACE_SV_Semaphore_Complex>. The first member, [0], is a counter used to know when all processes have finished with the <ACE_SV_Semaphore_Complex>. The counter is initialized to a large number, decremented on every create or open and incremented on every close. This way we can use the "adjust" feature provided by System V so that any process that exit's without calling <close> is accounted for. It doesn't help us if the last process does this (as we have no way of getting control to remove the <ACE_SV_Semaphore_Complex>) but it will work if any process other than the last does an exit (intentional or unintentional). The second member, [1], of the semaphore is used as a lock variable to avoid any race conditions in the <create> and <close> functions. The members beyond [1] are actual semaphore values in the array of semaphores, which may be sized by the user in the constructor.
ACE_SV_Semaphore_Complex::ACE_SV_Semaphore_Complex | ( | void | ) |
ACE_SV_Semaphore_Complex::ACE_SV_Semaphore_Complex | ( | key_t | key, | |
short | create = ACE_SV_Semaphore_Complex::ACE_CREATE , |
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int | initial_value = 1 , |
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u_short | nsems = 1 , |
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mode_t | perms = ACE_DEFAULT_FILE_PERMS | |||
) |
ACE_SV_Semaphore_Complex::ACE_SV_Semaphore_Complex | ( | const char * | name, | |
short | create = ACE_SV_Semaphore_Complex::ACE_CREATE , |
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int | initial_value = 1 , |
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u_short | nsems = 1 , |
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mode_t | perms = ACE_DEFAULT_FILE_PERMS | |||
) |
ACE_SV_Semaphore_Complex::~ACE_SV_Semaphore_Complex | ( | void | ) |
int ACE_SV_Semaphore_Complex::acquire | ( | u_short | n = 0 , |
|
short | flags = 0 | |||
) | const |
int ACE_SV_Semaphore_Complex::acquire_read | ( | u_short | n = 0 , |
|
short | flags = 0 | |||
) | const |
int ACE_SV_Semaphore_Complex::acquire_write | ( | u_short | n = 0 , |
|
short | flags = 0 | |||
) | const |
int ACE_SV_Semaphore_Complex::close | ( | void | ) |
Close an ACE_SV_Semaphore. Unlike the <remove> method, this method is for a process to call before it exits, when it is done with the ACE_SV_Semaphore. We "decrement" the counter of processes using the ACE_SV_Semaphore, and if this was the last one, we can remove the ACE_SV_Semaphore.
Reimplemented from ACE_SV_Semaphore_Simple.
int ACE_SV_Semaphore_Complex::control | ( | int | cmd, | |
int | value = 0 , |
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u_short | n = 0 | |||
) | const |
Reimplemented from ACE_SV_Semaphore_Simple.
int ACE_SV_Semaphore_Complex::control | ( | int | cmd, | |
semun | arg, | |||
u_short | n = 0 | |||
) | const |
Reimplemented from ACE_SV_Semaphore_Simple.
void ACE_SV_Semaphore_Complex::dump | ( | void | ) | const |
int ACE_SV_Semaphore_Complex::op | ( | sembuf | op_vec[], | |
u_short | nsems | |||
) | const |
General ACE_SV_Semaphore operation on an array of SV_Semaphores.
Reimplemented from ACE_SV_Semaphore_Simple.
int ACE_SV_Semaphore_Complex::op | ( | short | val, | |
u_short | semnum = 0 , |
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short | flags = 0 | |||
) | const |
General ACE_SV_Semaphore operation. Increment or decrement by a specific amount (positive or negative; amount can`t be zero).
Reimplemented from ACE_SV_Semaphore_Simple.
int ACE_SV_Semaphore_Complex::open | ( | key_t | key, | |
short | flags = ACE_SV_Semaphore_Simple::ACE_CREATE , |
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int | initial_value = 1 , |
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u_short | nsems = 1 , |
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mode_t | perms = ACE_DEFAULT_FILE_PERMS | |||
) |
Open or create an array of SV_Semaphores. We return 0 if all is OK, else -1.
Reimplemented from ACE_SV_Semaphore_Simple.
int ACE_SV_Semaphore_Complex::open | ( | const char * | name, | |
short | flags = ACE_SV_Semaphore_Simple::ACE_CREATE , |
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int | initial_value = 1 , |
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u_short | nsems = 1 , |
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mode_t | perms = ACE_DEFAULT_FILE_PERMS | |||
) |
Open or create an array of SV_Semaphores. We return 0 if all is OK, else -1.
Reimplemented from ACE_SV_Semaphore_Simple.
int ACE_SV_Semaphore_Complex::release | ( | u_short | n = 0 , |
|
short | flags = 0 | |||
) | const |
int ACE_SV_Semaphore_Complex::tryacquire | ( | u_short | n = 0 , |
|
short | flags = 0 | |||
) | const |
int ACE_SV_Semaphore_Complex::tryacquire_read | ( | u_short | n = 0 , |
|
short | flags = 0 | |||
) | const |
int ACE_SV_Semaphore_Complex::tryacquire_write | ( | u_short | n = 0 , |
|
short | flags = 0 | |||
) | const |
const int ACE_SV_Semaphore_Complex::BIGCOUNT_ = 10000 [static, private] |
sembuf ACE_SV_Semaphore_Complex::op_close_ [static, private] |
sembuf ACE_SV_Semaphore_Complex::op_endcreate_ [static, private] |
sembuf ACE_SV_Semaphore_Complex::op_lock_ [static, private] |
Initial value:
{ {0, 0, 0}, {0, 1, SEM_UNDO}, }
sembuf ACE_SV_Semaphore_Complex::op_open_ [static, private] |
Initial value:
{ {1, -1, SEM_UNDO}, }
sembuf ACE_SV_Semaphore_Complex::op_unlock_ [static, private] |
Initial value:
{ {0, -1, SEM_UNDO}, }