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diff --git a/doc/examples/io1.c b/doc/examples/io1.c
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+/**
+ * section: InputOutput
+ * synopsis: Example of custom Input/Output
+ * purpose: Demonstrate the use of xmlRegisterInputCallbacks
+ *          to build a custom I/O layer, this is used in an
+ *          XInclude method context to show how dynamic document can
+ *          be built in a clean way.
+ * usage: io1
+ * test: io1 > io1.tmp && diff io1.tmp $(srcdir)/io1.res
+ * author: Daniel Veillard
+ * copy: see Copyright for the status of this software.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <libxml/parser.h>
+#include <libxml/tree.h>
+#include <libxml/xinclude.h>
+#include <libxml/xmlIO.h>
+
+#ifdef LIBXML_XINCLUDE_ENABLED
+static const char *result = "<list><people>a</people><people>b</people></list>";
+static const char *cur = NULL;
+static int rlen;
+
+/**
+ * sqlMatch:
+ * @URI: an URI to test
+ *
+ * Check for an sql: query
+ *
+ * Returns 1 if yes and 0 if another Input module should be used
+ */
+static int
+sqlMatch(const char * URI) {
+    if ((URI != NULL) && (!strncmp(URI, "sql:", 4)))
+        return(1);
+    return(0);
+}
+
+/**
+ * sqlOpen:
+ * @URI: an URI to test
+ *
+ * Return a pointer to the sql: query handler, in this example simply
+ * the current pointer...
+ *
+ * Returns an Input context or NULL in case or error
+ */
+static void *
+sqlOpen(const char * URI) {
+    if ((URI == NULL) || (strncmp(URI, "sql:", 4)))
+        return(NULL);
+    cur = result;
+    rlen = strlen(result);
+    return((void *) cur);
+}
+
+/**
+ * sqlClose:
+ * @context: the read context
+ *
+ * Close the sql: query handler
+ *
+ * Returns 0 or -1 in case of error
+ */
+static int
+sqlClose(void * context) {
+    if (context == NULL) return(-1);
+    cur = NULL;
+    rlen = 0;
+    return(0);
+}
+
+/**
+ * sqlRead:
+ * @context: the read context
+ * @buffer: where to store data
+ * @len: number of bytes to read
+ *
+ * Implement an sql: query read.
+ *
+ * Returns the number of bytes read or -1 in case of error
+ */
+static int
+sqlRead(void * context, char * buffer, int len) {
+   const char *ptr = (const char *) context;
+
+   if ((context == NULL) || (buffer == NULL) || (len < 0))
+       return(-1);
+
+   if (len > rlen) len = rlen;
+   memcpy(buffer, ptr, len);
+   rlen -= len;
+   return(len);
+}
+
+const char *include = "<?xml version='1.0'?>\n\
+<document xmlns:xi=\"http://www.w3.org/2003/XInclude\">\n\
+  <p>List of people:</p>\n\
+  <xi:include href=\"sql:select_name_from_people\"/>\n\
+</document>\n";
+
+int main(void) {
+    xmlDocPtr doc;
+
+    /*
+     * this initialize the library and check potential ABI mismatches
+     * between the version it was compiled for and the actual shared
+     * library used.
+     */
+    LIBXML_TEST_VERSION
+
+    /*
+     * register the new I/O handlers
+     */
+    if (xmlRegisterInputCallbacks(sqlMatch, sqlOpen, sqlRead, sqlClose) < 0) {
+        fprintf(stderr, "failed to register SQL handler\n");
+	exit(1);
+    }
+    /*
+     * parse include into a document
+     */
+    doc = xmlReadMemory(include, strlen(include), "include.xml", NULL, 0);
+    if (doc == NULL) {
+        fprintf(stderr, "failed to parse the including file\n");
+	exit(1);
+    }
+
+    /*
+     * apply the XInclude process, this should trigger the I/O just
+     * registered.
+     */
+    if (xmlXIncludeProcess(doc) <= 0) {
+        fprintf(stderr, "XInclude processing failed\n");
+	exit(1);
+    }
+
+#ifdef LIBXML_OUTPUT_ENABLED
+    /*
+     * save the output for checking to stdout
+     */
+    xmlDocDump(stdout, doc);
+#endif
+
+    /*
+     * Free the document
+     */
+    xmlFreeDoc(doc);
+
+    /*
+     * Cleanup function for the XML library.
+     */
+    xmlCleanupParser();
+    /*
+     * this is to debug memory for regression tests
+     */
+    xmlMemoryDump();
+    return(0);
+}
+#else
+int main(void) {
+    fprintf(stderr, "XInclude support not compiled in\n");
+    exit(1);
+}
+#endif