From: wessels <>
Date: Sat, 22 May 1999 05:34:11 +0000 (+0000)
Subject: document storeIOState->offset
X-Git-Tag: SQUID_3_0_PRE1~2188
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2324dde2792b708d13a09057c4a3edf7fb3859a7;p=thirdparty%2Fsquid.git

document storeIOState->offset
---

diff --git a/doc/Programming-Guide/prog-guide.sgml b/doc/Programming-Guide/prog-guide.sgml
index 5077aa3d4c..226ceb165e 100644
--- a/doc/Programming-Guide/prog-guide.sgml
+++ b/doc/Programming-Guide/prog-guide.sgml
@@ -718,6 +718,14 @@ Squid consists of the following major components
 	<em/swap_file_number/ is the 32-bit swap file number for the
 	object, taken from the <em/StoreEntry/.
 
+	<em/offset/ represents the file (byte) offset after the
+	last operation completed.  For example, after a read operation,
+	<em/offset/ must be incremented by the number of bytes read.
+	The same goes for write operations.  This means that the
+	filesystem layer needs explicit (callback) notification
+	for writes.  It is wrong to increment <em/offset/ before
+	an I/O operation has been known to succeed.
+
 	Note that there are two callback functions.  The first,
 	<em/callback/, of type <em/STIOCB/ (store I/O callback),
 	is callback for the <em/storeIOState/ as a whole.  This
@@ -890,6 +898,15 @@ Squid consists of the following major components
 	called if the read operation is successful.  If it fails,
 	then the <em/STIOCB/ callback will be called instead.
 
+<sect2>Todo...
+
+	<P>
+	Note there is much work yet to be done in defining
+	this programming interface.  All of the code for
+	rebuilding the disk store at startup is still very
+	UFS-specific.  The configuration file and <em/SquidConfig/
+	data structures are still sort of specific to UFS.
+
 
 <!-- %%%% Chapter : FORWARDING SELECTION %%%% -->
 <sect>Forwarding Selection