.TH ACE_SV_Semaphore_Complex 3 "1 Dec 2001" "ACE" \" -*- nroff -*-
.ad l
.nh
.SH NAME
ACE_SV_Semaphore_Complex \- This is a more complex semaphore wrapper that handles race conditions for initialization correctly... 
.SH SYNOPSIS
.br
.PP
\fC#include <SV_Semaphore_Complex.h>\fR
.PP
Inherits \fBACE_SV_Semaphore_Simple\fR.
.PP
.SS Public Types

.in +1c
.ti -1c
.RI "enum { \fBACE_CREATE\fR = IPC_CREAT, \fBACE_OPEN\fR = 0 }"
.br
.in -1c
.SS Public Methods

.in +1c
.ti -1c
.RI "\fBACE_SV_Semaphore_Complex\fR (void)"
.br
.ti -1c
.RI "\fBACE_SV_Semaphore_Complex\fR (key_t key, int create = ACE_SV_Semaphore_Complex::ACE_CREATE, int initial_value = 1, u_short nsems = 1, int perms = ACE_DEFAULT_FILE_PERMS)"
.br
.ti -1c
.RI "\fBACE_SV_Semaphore_Complex\fR (const char *name, int create = ACE_SV_Semaphore_Complex::ACE_CREATE, int initial_value = 1, u_short nsems = 1, int perms = ACE_DEFAULT_FILE_PERMS)"
.br
.ti -1c
.RI "\fB~ACE_SV_Semaphore_Complex\fR (void)"
.br
.ti -1c
.RI "int \fBopen\fR (const char *name, int flags = ACE_SV_Semaphore_Simple::ACE_CREATE, int initial_value = 1, u_short nsems = 1, int perms = ACE_DEFAULT_FILE_PERMS)"
.br
.RI "\fIOpen or create an array of SV_Semaphores. We return 0 if all is OK, else -1.\fR"
.ti -1c
.RI "int \fBopen\fR (key_t key, int flags = ACE_SV_Semaphore_Simple::ACE_CREATE, int initial_value = 1, u_short nsems = 1, int perms = ACE_DEFAULT_FILE_PERMS)"
.br
.RI "\fIOpen or create an array of SV_Semaphores. We return 0 if all is OK, else -1.\fR"
.ti -1c
.RI "int \fBclose\fR (void)"
.br
.ti -1c
.RI "int \fBacquire\fR (u_short n = 0, int flags = 0) const"
.br
.RI "\fIAcquire the semaphore.\fR"
.ti -1c
.RI "int \fBacquire_read\fR (u_short n = 0, int flags = 0) const"
.br
.RI "\fIAcquire a semaphore for reading.\fR"
.ti -1c
.RI "int \fBacquire_write\fR (u_short n = 0, int flags = 0) const"
.br
.RI "\fIAcquire a semaphore for writing.\fR"
.ti -1c
.RI "int \fBtryacquire\fR (u_short n = 0, int flags = 0) const"
.br
.RI "\fITry to acquire the semaphore.\fR"
.ti -1c
.RI "int \fBtryacquire_read\fR (u_short n = 0, int flags = 0) const"
.br
.RI "\fITry to acquire the semaphore for reading.\fR"
.ti -1c
.RI "int \fBtryacquire_write\fR (u_short n = 0, int flags = 0) const"
.br
.RI "\fITry to acquire the semaphore for writing.\fR"
.ti -1c
.RI "int \fBrelease\fR (u_short n = 0, int flags = 0) const"
.br
.RI "\fIRelease the semaphore.\fR"
.ti -1c
.RI "int \fBop\fR (int val, u_short n = 0, int flags = 0) const"
.br
.RI "\fIGeneral ACE_SV_Semaphore operation. Increment or decrement by a specific amount (positive or negative; amount can`t be zero).\fR"
.ti -1c
.RI "int \fBop\fR (sembuf op_vec[], u_short n) const"
.br
.RI "\fIGeneral ACE_SV_Semaphore operation on an array of SV_Semaphores.\fR"
.ti -1c
.RI "int \fBcontrol\fR (int cmd, \fBsemun\fR arg, u_short n = 0) const"
.br
.ti -1c
.RI "int \fBcontrol\fR (int cmd, int value = 0, u_short n = 0) const"
.br
.ti -1c
.RI "void \fBdump\fR (void) const"
.br
.RI "\fIDump the state of an object.\fR"
.in -1c
.SS Public Attributes

.in +1c
.ti -1c
.RI "\fBACE_ALLOC_HOOK_DECLARE\fR"
.br
.RI "\fIDeclare the dynamic allocation hooks.\fR"
.in -1c
.SS Static Private Attributes

.in +1c
.ti -1c
.RI "const int \fBBIGCOUNT_\fR"
.br
.ti -1c
.RI "sembuf \fBop_lock_\fR [2]"
.br
.ti -1c
.RI "sembuf \fBop_endcreate_\fR [2]"
.br
.ti -1c
.RI "sembuf \fBop_open_\fR [1]"
.br
.ti -1c
.RI "sembuf \fBop_close_\fR [3]"
.br
.ti -1c
.RI "sembuf \fBop_unlock_\fR [1]"
.br
.in -1c
.SH DETAILED DESCRIPTION
.PP 
This is a more complex semaphore wrapper that handles race conditions for initialization correctly...
.PP
.PP
 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 . The first member, [0], is a counter used to know when all processes have finished with the . 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 ) 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. 
.PP
.SH MEMBER ENUMERATION DOCUMENTATION
.PP 
.SS anonymous enum
.PP
\fBEnumeration values:\fR
.in +1c
.TP
\fB\fIACE_CREATE\fR \fR
.TP
\fB\fIACE_OPEN\fR \fR
.SH CONSTRUCTOR & DESTRUCTOR DOCUMENTATION
.PP 
.SS ACE_SV_Semaphore_Complex::ACE_SV_Semaphore_Complex (void)
.PP
.SS ACE_SV_Semaphore_Complex::ACE_SV_Semaphore_Complex (key_t key, int create = ACE_SV_Semaphore_Complex::ACE_CREATE, int initial_value = 1, u_short nsems = 1, int perms = ACE_DEFAULT_FILE_PERMS)
.PP
.SS ACE_SV_Semaphore_Complex::ACE_SV_Semaphore_Complex (const char * name, int create = ACE_SV_Semaphore_Complex::ACE_CREATE, int initial_value = 1, u_short nsems = 1, int perms = ACE_DEFAULT_FILE_PERMS)
.PP
.SS ACE_SV_Semaphore_Complex::~ACE_SV_Semaphore_Complex (void)
.PP
.SH MEMBER FUNCTION DOCUMENTATION
.PP 
.SS int ACE_SV_Semaphore_Complex::acquire (u_short n = 0, int flags = 0) const
.PP
Acquire the semaphore.
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS int ACE_SV_Semaphore_Complex::acquire_read (u_short n = 0, int flags = 0) const
.PP
Acquire a semaphore for reading.
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS int ACE_SV_Semaphore_Complex::acquire_write (u_short n = 0, int flags = 0) const
.PP
Acquire a semaphore for writing.
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS int ACE_SV_Semaphore_Complex::close (void)
.PP
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. 
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS int ACE_SV_Semaphore_Complex::control (int cmd, int value = 0, u_short n = 0) const
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS int ACE_SV_Semaphore_Complex::control (int cmd, \fBsemun\fR arg, u_short n = 0) const
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS void ACE_SV_Semaphore_Complex::dump (void) const
.PP
Dump the state of an object.
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS int ACE_SV_Semaphore_Complex::op (sembuf op_vec[], u_short n) const
.PP
General ACE_SV_Semaphore operation on an array of SV_Semaphores.
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS int ACE_SV_Semaphore_Complex::op (int val, u_short n = 0, int flags = 0) const
.PP
General ACE_SV_Semaphore operation. Increment or decrement by a specific amount (positive or negative; amount can`t be zero).
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS int ACE_SV_Semaphore_Complex::open (key_t key, int flags = ACE_SV_Semaphore_Simple::ACE_CREATE, int initial_value = 1, u_short nsems = 1, int perms = ACE_DEFAULT_FILE_PERMS)
.PP
Open or create an array of SV_Semaphores. We return 0 if all is OK, else -1.
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS int ACE_SV_Semaphore_Complex::open (const char * name, int flags = ACE_SV_Semaphore_Simple::ACE_CREATE, int initial_value = 1, u_short nsems = 1, int perms = ACE_DEFAULT_FILE_PERMS)
.PP
Open or create an array of SV_Semaphores. We return 0 if all is OK, else -1.
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS int ACE_SV_Semaphore_Complex::release (u_short n = 0, int flags = 0) const
.PP
Release the semaphore.
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS int ACE_SV_Semaphore_Complex::tryacquire (u_short n = 0, int flags = 0) const
.PP
Try to acquire the semaphore.
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS int ACE_SV_Semaphore_Complex::tryacquire_read (u_short n = 0, int flags = 0) const
.PP
Try to acquire the semaphore for reading.
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS int ACE_SV_Semaphore_Complex::tryacquire_write (u_short n = 0, int flags = 0) const
.PP
Try to acquire the semaphore for writing.
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SH MEMBER DATA DOCUMENTATION
.PP 
.SS ACE_SV_Semaphore_Complex::ACE_ALLOC_HOOK_DECLARE
.PP
Declare the dynamic allocation hooks.
.PP
Reimplemented from \fBACE_SV_Semaphore_Simple\fR.
.SS const int ACE_SV_Semaphore_Complex::BIGCOUNT_\fC [static, private]\fR
.PP
.SS sembuf ACE_SV_Semaphore_Complex::op_close_[3]\fC [static, private]\fR
.PP
.SS sembuf ACE_SV_Semaphore_Complex::op_endcreate_[2]\fC [static, private]\fR
.PP
.SS sembuf ACE_SV_Semaphore_Complex::op_lock_[2]\fC [static, private]\fR
.PP
.SS sembuf ACE_SV_Semaphore_Complex::op_open_[1]\fC [static, private]\fR
.PP
.SS sembuf ACE_SV_Semaphore_Complex::op_unlock_[1]\fC [static, private]\fR
.PP


.SH AUTHOR
.PP 
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