diff --git a/parserInternals.c b/parserInternals.c
index a2fe5aad..6a43cc8f 100644
--- a/parserInternals.c
+++ b/parserInternals.c
@@ -136,6 +136,9 @@ xmlCtxtErrMemory(xmlParserCtxtPtr ctxt)
     xmlGenericErrorFunc channel = NULL;
     void *data;
 
+    if (ctxt == NULL)
+        return;
+
     ctxt->errNo = XML_ERR_NO_MEMORY;
     ctxt->instate = XML_PARSER_EOF; /* TODO: Remove after refactoring */
     ctxt->wellFormed = 0;
@@ -1141,6 +1144,9 @@ xmlSwitchInputEncodingName(xmlParserCtxtPtr ctxt, xmlParserInputPtr input,
  */
 int
 xmlSwitchEncodingName(xmlParserCtxtPtr ctxt, const char *encoding) {
+    if (ctxt == NULL)
+        return(-1);
+
     return(xmlSwitchInputEncodingName(ctxt, ctxt->input, encoding));
 }
 
diff --git a/pattern.c b/pattern.c
index 2b669768..23b52744 100644
--- a/pattern.c
+++ b/pattern.c
@@ -2276,6 +2276,9 @@ xmlPatternCompileSafe(const xmlChar *pattern, xmlDict *dict, int flags,
     int streamable = 1;
     int error;
 
+    if (patternOut == NULL)
+        return(1);
+
     if (pattern == NULL) {
         error = 1;
         goto error;
diff --git a/uri.c b/uri.c
index 3803e0de..370b449f 100644
--- a/uri.c
+++ b/uri.c
@@ -980,8 +980,9 @@ xmlParseURISafe(const char *str, xmlURIPtr *uriOut) {
     xmlURIPtr uri;
     int ret;
 
-    if (uriOut != NULL)
-        *uriOut = NULL;
+    if (uriOut == NULL)
+        return(1);
+    *uriOut = NULL;
     if (str == NULL)
 	return(1);
 
@@ -995,8 +996,7 @@ xmlParseURISafe(const char *str, xmlURIPtr *uriOut) {
         return(ret);
     }
 
-    if (uriOut != NULL)
-        *uriOut = uri;
+    *uriOut = uri;
     return(0);
 }
 
@@ -2016,6 +2016,9 @@ xmlBuildURISafe(const xmlChar *URI, const xmlChar *base, xmlChar **valPtr) {
     xmlURIPtr bas = NULL;
     xmlURIPtr res = NULL;
 
+    if (valPtr == NULL)
+        return(1);
+
     /*
      * 1) The URI reference is parsed into the potential four components and
      *    fragment identifier, as described in Section 4.3.