Document that the POSIX API is not thread-safe.

doc/html/pcre2api.html

@@ -461,7 +461,7 @@ <h1>pcre2api man page</h1>
 PCRE2 has its own native API, which is described in this document. There are
 also some wrapper functions for the 8-bit library that correspond to the
 POSIX regular expression API, but they do not give access to all the
-functionality of PCRE2. They are described in the
+functionality of PCRE2 and they are not thread-safe. They are described in the
 <a href="pcre2posix.html"><b>pcre2posix</b></a>
 documentation. Both these APIs define a set of C function calls.
 </P>
@@ -4140,7 +4140,7 @@ <h1>pcre2api man page</h1>
 </P>
 <br><a name="SEC43" href="#TOC1">REVISION</a><br>
 <P>
-Last updated: 11 November 2023
+Last updated: 14 November 2023
 <br>
 Copyright &copy; 1997-2023 University of Cambridge.
 <br>

doc/html/pcre2posix.html

@@ -53,9 +53,13 @@ <h1>pcre2posix man page</h1>
 additional functionality.
 </P>
 <P>
-The functions described here are wrapper functions that ultimately call the
-PCRE2 native API. Their prototypes are defined in the <b>pcre2posix.h</b> header
-file, and they all have unique names starting with <b>pcre2_</b>. However, the
+<b>IMPORTANT NOTE</b>: The functions described here are NOT thread-safe, and
+should not be used in multi-threaded applications. Use the native API instead.
+</P>
+<P>
+These functions are wrapper functions that ultimately call the PCRE2 native
+API. Their prototypes are defined in the <b>pcre2posix.h</b> header file, and
+they all have unique names starting with <b>pcre2_</b>. However, the
 <b>pcre2posix.h</b> header also contains macro definitions that convert the
 standard POSIX names such <b>regcomp()</b> into <b>pcre2_regcomp()</b> etc. This
 means that a program can use the usual POSIX names without running the risk of
@@ -93,6 +97,11 @@ <h1>pcre2posix man page</h1>
 </P>
 <br><a name="SEC3" href="#TOC1">USING THE POSIX FUNCTIONS</a><br>
 <P>
+Note that these functions are just POSIX-style wrappers for PCRE2's native API.
+They do not give POSIX regular expression behaviour, and they are not
+thread-safe.
+</P>
+<P>
 Those POSIX option bits that can reasonably be mapped to PCRE2 native options
 have been implemented. In addition, the option REG_EXTENDED is defined with the
 value zero. This has no effect, but since programs that are written to the
@@ -123,8 +132,10 @@ <h1>pcre2posix man page</h1>
 internal form. By default, the pattern is a C string terminated by a binary
 zero (but see REG_PEND below). The <i>preg</i> argument is a pointer to a
 <b>regex_t</b> structure that is used as a base for storing information about
-the compiled regular expression. (It is also used for input when REG_PEND is
-set.)
+the compiled regular expression. It is also used for input when REG_PEND is
+set. The <b>regex_t</b> structure used by <b>pcre2_regcomp()</b> is defined in
+<b>pcre2posix.h</b> and is not the same as the structure used by other libraries
+that provide POSIX-style matching.
 </P>
 <P>
 The argument <i>cflags</i> is either zero, or contains one or more of the bits
@@ -353,9 +364,9 @@ <h1>pcre2posix man page</h1>
 </P>
 <br><a name="SEC10" href="#TOC1">REVISION</a><br>
 <P>
-Last updated: 26 April 2021
+Last updated: 14 November 2023
 <br>
-Copyright &copy; 1997-2021 University of Cambridge.
+Copyright &copy; 1997-2023 University of Cambridge.
 <br>
 <p>
 Return to the <a href="index.html">PCRE2 index page</a>.