.TH ACE_File_Lock 3 "1 Dec 2001" "ACE" \" -*- nroff -*-
.ad l
.nh
.SH NAME
ACE_File_Lock \- A wrapper around the UNIX file locking mechanism. 
.SH SYNOPSIS
.br
.PP
\fC#include <File_Lock.h>\fR
.PP
.SS Public Methods

.in +1c
.ti -1c
.RI "\fBACE_File_Lock\fR (ACE_HANDLE handle = ACE_INVALID_HANDLE, int unlink_in_destructor = 1)"
.br
.ti -1c
.RI "\fBACE_File_Lock\fR (const \fBACE_TCHAR\fR *filename, int flags, \fBmode_t\fR mode = 0, int unlink_in_destructor = 1)"
.br
.RI "\fIOpen the <filename> with <flags> and <mode> and set the result to <handle_>. If you don't want the file unlinked in the destructor pass a zero value for <unlink_in_destructor>.\fR"
.ti -1c
.RI "int \fBopen\fR (const \fBACE_TCHAR\fR *filename, int flags, \fBmode_t\fR mode = 0)"
.br
.RI "\fIOpen the <filename> with <flags> and <mode> and set the result to <handle_>.\fR"
.ti -1c
.RI "\fB~ACE_File_Lock\fR (void)"
.br
.RI "\fIRemove a File lock by releasing it and closing down the <handle_>.\fR"
.ti -1c
.RI "int \fBremove\fR (int unlink_file = 1)"
.br
.RI "\fIRemove a File lock by releasing it and closing down the <handle_>. If <unlink_file> is non-0 then we unlink the file.\fR"
.ti -1c
.RI "int \fBacquire\fR (short whence = 0, off_t start = 0, off_t len = 1)"
.br
.ti -1c
.RI "int \fBtryacquire\fR (short whence = 0, off_t start = 0, off_t len = 1)"
.br
.ti -1c
.RI "int \fBrelease\fR (short whence = 0, off_t start = 0, off_t len = 1)"
.br
.RI "\fIUnlock a readers/writer lock.\fR"
.ti -1c
.RI "int \fBacquire_write\fR (short whence = 0, off_t start = 0, off_t len = 1)"
.br
.RI "\fIAcquire a write lock, but block if any readers or a writer hold the lock.\fR"
.ti -1c
.RI "int \fBtryacquire_write\fR (short whence = 0, off_t start = 0, off_t len = 1)"
.br
.ti -1c
.RI "int \fBtryacquire_write_upgrade\fR (short whence = 0, off_t start = 0, off_t len = 1)"
.br
.ti -1c
.RI "int \fBacquire_read\fR (short whence = 0, off_t start = 0, off_t len = 1)"
.br
.ti -1c
.RI "int \fBtryacquire_read\fR (short whence = 0, off_t start = 0, off_t len = 1)"
.br
.ti -1c
.RI "ACE_HANDLE \fBget_handle\fR (void) const"
.br
.RI "\fIGet underlying  for the file.\fR"
.ti -1c
.RI "void \fBset_handle\fR (ACE_HANDLE)"
.br
.ti -1c
.RI "void \fBdump\fR (void) const"
.br
.RI "\fIDump state of the 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 Protected Attributes

.in +1c
.ti -1c
.RI "\fBACE_OS::ace_flock_t\fR \fBlock_\fR"
.br
.RI "\fILocking structure for OS record locks.\fR"
.ti -1c
.RI "int \fBremoved_\fR"
.br
.RI "\fIKeeps track of whether <remove> has been called yet to avoid multiple <remove> calls, e.g., explicitly and implicitly in the destructor. This flag isn't protected by a lock, so make sure that you don't have multiple threads simultaneously calling <remove> on the same object, which is a bad idea anyway...\fR"
.ti -1c
.RI "int \fBunlink_in_destructor_\fR"
.br
.RI "\fIKeeps track of whether to unlink the underlying file in the destructor.\fR"
.in -1c
.SS Private Methods

.in +1c
.ti -1c
.RI "void \fBoperator=\fR (const ACE_File_Lock &)"
.br
.ti -1c
.RI "\fBACE_File_Lock\fR (const ACE_File_Lock &)"
.br
.in -1c
.SH DETAILED DESCRIPTION
.PP 
A wrapper around the UNIX file locking mechanism.
.PP
.PP
 Allows us to "adapt" the UNIX file locking mechanisms to work with all of our Guard stuff... 
.PP
.SH CONSTRUCTOR & DESTRUCTOR DOCUMENTATION
.PP 
.SS ACE_File_Lock::ACE_File_Lock (ACE_HANDLE handle = ACE_INVALID_HANDLE, int unlink_in_destructor = 1)
.PP
Set the <handle_> of the File_Lock to <handle>. Note that this constructor assumes ownership of the <handle> and will close it down in <remove>. If you want the <handle> to stay open when <remove> is called make sure to call <dup> on the <handle>. If you don't want the file unlinked in the destructor pass a zero value for <unlink_in_destructor>. 
.SS ACE_File_Lock::ACE_File_Lock (const \fBACE_TCHAR\fR * filename, int flags, \fBmode_t\fR mode = 0, int unlink_in_destructor = 1)
.PP
Open the <filename> with <flags> and <mode> and set the result to <handle_>. If you don't want the file unlinked in the destructor pass a zero value for <unlink_in_destructor>.
.PP
.SS ACE_File_Lock::~ACE_File_Lock (void)
.PP
Remove a File lock by releasing it and closing down the <handle_>.
.PP
.SS ACE_File_Lock::ACE_File_Lock (const ACE_File_Lock &)\fC [private]\fR
.PP
.SH MEMBER FUNCTION DOCUMENTATION
.PP 
.SS int ACE_File_Lock::acquire (short whence = 0, off_t start = 0, off_t len = 1)
.PP
Note, for interface uniformity with other synchronization wrappers we include the  method. This is implemented as a write-lock to be on the safe-side... 
.SS int ACE_File_Lock::acquire_read (short whence = 0, off_t start = 0, off_t len = 1)
.PP
Acquire a read lock, but block if a writer hold the lock. Returns -1 on failure. If we "failed" because someone else already had the lock, <errno> is set to <EBUSY>. 
.SS int ACE_File_Lock::acquire_write (short whence = 0, off_t start = 0, off_t len = 1)
.PP
Acquire a write lock, but block if any readers or a writer hold the lock.
.PP
.SS void ACE_File_Lock::dump (void) const
.PP
Dump state of the object.
.PP
.SS ACE_HANDLE ACE_File_Lock::get_handle (void) const
.PP
Get underlying  for the file.
.PP
.SS int ACE_File_Lock::open (const \fBACE_TCHAR\fR * filename, int flags, \fBmode_t\fR mode = 0)
.PP
Open the <filename> with <flags> and <mode> and set the result to <handle_>.
.PP
.SS void ACE_File_Lock::operator= (const ACE_File_Lock &)\fC [private]\fR
.PP
.SS int ACE_File_Lock::release (short whence = 0, off_t start = 0, off_t len = 1)
.PP
Unlock a readers/writer lock.
.PP
.SS int ACE_File_Lock::remove (int unlink_file = 1)
.PP
Remove a File lock by releasing it and closing down the <handle_>. If <unlink_file> is non-0 then we unlink the file.
.PP
.SS void ACE_File_Lock::set_handle (ACE_HANDLE)
.PP
Set underlying . Note that this method assumes ownership of the <handle> and will close it down in <remove>. If you want the <handle> to stay open when <remove> is called make sure to call <dup> on the <handle> before closing it. You are responsible for the closing the existing <handle> before overwriting it. 
.SS int ACE_File_Lock::tryacquire (short whence = 0, off_t start = 0, off_t len = 1)
.PP
Note, for interface uniformity with other synchronization wrappers we include the <tryacquire> method. This is implemented as a write-lock to be on the safe-side... Returns -1 on failure. If we "failed" because someone else already had the lock, <errno> is set to <EBUSY>. 
.SS int ACE_File_Lock::tryacquire_read (short whence = 0, off_t start = 0, off_t len = 1)
.PP
Conditionally acquire a read lock (i.e., won't block). Returns -1 on failure. If we "failed" because someone else already had the lock, <errno> is set to <EBUSY>. 
.SS int ACE_File_Lock::tryacquire_write (short whence = 0, off_t start = 0, off_t len = 1)
.PP
Conditionally acquire a write lock (i.e., won't block). Returns -1 on failure. If we "failed" because someone else already had the lock, <errno> is set to <EBUSY>. 
.SS int ACE_File_Lock::tryacquire_write_upgrade (short whence = 0, off_t start = 0, off_t len = 1)
.PP
Conditionally upgrade to a write lock (i.e., won't block). Returns -1 on failure. If we "failed" because someone else already had the lock, <errno> is set to <EBUSY>. 
.SH MEMBER DATA DOCUMENTATION
.PP 
.SS ACE_File_Lock::ACE_ALLOC_HOOK_DECLARE
.PP
Declare the dynamic allocation hooks.
.PP
.SS \fBACE_OS::ace_flock_t\fR ACE_File_Lock::lock_\fC [protected]\fR
.PP
Locking structure for OS record locks.
.PP
.SS int ACE_File_Lock::removed_\fC [protected]\fR
.PP
Keeps track of whether <remove> has been called yet to avoid multiple <remove> calls, e.g., explicitly and implicitly in the destructor. This flag isn't protected by a lock, so make sure that you don't have multiple threads simultaneously calling <remove> on the same object, which is a bad idea anyway...
.PP
.SS int ACE_File_Lock::unlink_in_destructor_\fC [protected]\fR
.PP
Keeps track of whether to unlink the underlying file in the destructor.
.PP


.SH AUTHOR
.PP 
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