3 files changed, 34 insertions, 19 deletions
diff --git a/doc/html/NON-AUTOTOOLS-BUILD.txt b/doc/html/NON-AUTOTOOLS-BUILD.txt
index a73c058..2ce0fd5 100644
--- a/doc/html/NON-AUTOTOOLS-BUILD.txt
+++ b/doc/html/NON-AUTOTOOLS-BUILD.txt
@@ -40,7 +40,11 @@ GENERIC INSTRUCTIONS FOR THE PCRE2 C LIBRARY
 
 The following are generic instructions for building the PCRE2 C library "by
 hand". If you are going to use CMake, this section does not apply to you; you
-can skip ahead to the CMake section.
+can skip ahead to the CMake section. Note that the settings concerned with 
+8-bit, 16-bit, and 32-bit code units relate to the type of data string that 
+PCRE2 processes. They are NOT referring to the underlying operating system bit 
+width. You do not have to do anything special to compile in a 64-bit
+environment, for example.
 
  (1) Copy or rename the file src/config.h.generic as src/config.h, and edit the
      macro settings that it contains to whatever is appropriate for your
@@ -86,11 +90,11 @@ can skip ahead to the CMake section.
      The tables in src/pcre2_chartables.c are defaults. The caller of PCRE2 can
      specify alternative tables at run time.
 
- (4) For an 8-bit library, compile the following source files from the src
-     directory, setting -DPCRE2_CODE_UNIT_WIDTH=8 as a compiler option. Also
-     set -DHAVE_CONFIG_H if you have set up src/config.h with your
-     configuration, or else use other -D settings to change the configuration
-     as required.
+ (4) For a library that supports 8-bit code units in the character strings that 
+     it processes, compile the following source files from the src directory,
+     setting -DPCRE2_CODE_UNIT_WIDTH=8 as a compiler option. Also set
+     -DHAVE_CONFIG_H if you have set up src/config.h with your configuration,
+     or else use other -D settings to change the configuration as required.
 
        pcre2_auto_possess.c
        pcre2_chartables.c
@@ -142,9 +146,9 @@ can skip ahead to the CMake section.
      If your system has static and shared libraries, you may have to do this
      once for each type.
 
- (6) If you want to build a 16-bit library or 32-bit library (as well as, or
-     instead of the 8-bit library) just supply 16 or 32 as the value of
-     -DPCRE2_CODE_UNIT_WIDTH when you are compiling.
+ (6) If you want to build a library that supports 16-bit or 32-bit code units,
+     (as well as, or instead of the 8-bit library) just supply 16 or 32 as the
+     value of -DPCRE2_CODE_UNIT_WIDTH when you are compiling.
 
  (7) If you want to build the POSIX wrapper functions (which apply only to the
      8-bit library), ensure that you have the src/pcre2posix.h file and then
@@ -401,6 +405,6 @@ Everything in that location, source and executable, is in EBCDIC and native
 z/OS file formats. The port provides an API for LE languages such as COBOL and
 for the z/OS and z/VM versions of the Rexx languages.
 
-==============================
-Last Updated: 14 November 2018
-==============================
+===========================
+Last Updated: 28 April 2021
+===========================
diff --git a/doc/html/pcre2.html b/doc/html/pcre2.html
index dc2d058..1e267d0 100644
--- a/doc/html/pcre2.html
+++ b/doc/html/pcre2.html
@@ -38,8 +38,14 @@ Oniguruma syntax items, and there are options for requesting some minor changes
 that give better ECMAScript (aka JavaScript) compatibility.
 </P>
 <P>
-The source code for PCRE2 can be compiled to support 8-bit, 16-bit, or 32-bit
-code units, which means that up to three separate libraries may be installed.
+The source code for PCRE2 can be compiled to support strings of 8-bit, 16-bit,
+or 32-bit code units, which means that up to three separate libraries may be
+installed, one for each code unit size. The size of code unit is not related to
+the bit size of the underlying hardware. In a 64-bit environment that also
+supports 32-bit applications, versions of PCRE2 that are compiled in both
+64-bit and 32-bit modes may be needed.
+</P>
+<P>
 The original work to extend PCRE to 16-bit and 32-bit code units was done by
 Zoltan Herczeg and Christian Persch, respectively. In all three cases, strings
 can be interpreted either as one character per code unit, or as UTF-encoded
@@ -198,9 +204,9 @@ use my two initials, followed by the two digits 10, at the domain cam.ac.uk.
 </P>
 <br><a name="SEC5" href="#TOC1">REVISION</a><br>
 <P>
-Last updated: 17 September 2018
+Last updated: 28 April 2021
 <br>
-Copyright &copy; 1997-2018 University of Cambridge.
+Copyright &copy; 1997-2021 University of Cambridge.
 <br>
 <p>
 Return to the <a href="index.html">PCRE2 index page</a>.
diff --git a/doc/html/pcre2test.html b/doc/html/pcre2test.html
index 4a7e55f..3a7a9b7 100644
--- a/doc/html/pcre2test.html
+++ b/doc/html/pcre2test.html
@@ -1213,7 +1213,7 @@ Setting match controls
 The following modifiers affect the matching process or request additional
 information. Some of them may also be specified on a pattern line (see above),
 in which case they apply to every subject line that is matched against that
-pattern.
+pattern, but can be overridden by modifiers on the subject.
 <pre>
       aftertext                  show text after match
       allaftertext               show text after captures
@@ -1421,6 +1421,11 @@ replacement strings cannot contain commas, because a comma signifies the end of
 a modifier. This is not thought to be an issue in a test program.
 </P>
 <P>
+Specifying a completely empty replacement string disables this modifier. 
+However, it is possible to specify an empty replacement by providing a buffer 
+length, as described below, for an otherwise empty replacement.
+</P>
+<P>
 Unlike subject strings, <b>pcre2test</b> does not process replacement strings
 for escape sequences. In UTF mode, a replacement string is checked to see if it
 is a valid UTF-8 string. If so, it is correctly converted to a UTF string of
@@ -2119,9 +2124,9 @@ Cambridge, England.
 </P>
 <br><a name="SEC21" href="#TOC1">REVISION</a><br>
 <P>
-Last updated: 14 September 2020
+Last updated: 28 April 2021
 <br>
-Copyright &copy; 1997-2020 University of Cambridge.
+Copyright &copy; 1997-2021 University of Cambridge.
 <br>
 <p>
 Return to the <a href="index.html">PCRE2 index page</a>.