diff --git a/cfg/posix.cfg b/cfg/posix.cfg
index bceb9af40..d6c53331e 100644
--- a/cfg/posix.cfg
+++ b/cfg/posix.cfg
@@ -4580,6 +4580,24 @@ The function 'mktemp' is considered to be dangerous due to race conditions and s
       <not-bool/>
     </arg>
   </function>
+  <!-- https://man7.org/linux/man-pages/man3/wcswidth.3.html -->
+  <!-- int wcswidth(const wchar_t *s, size_t n); -->
+  <function name="wcswidth">
+    <returnValue type="int"/>
+    <use-retval/>
+    <noreturn>false</noreturn>
+    <leak-ignore/>
+    <arg nr="1" direction="in">
+      <not-null/>
+      <not-uninit/>
+      <not-bool/>
+    </arg>
+    <arg nr="2" direction="in">
+      <not-uninit/>
+      <not-bool/>
+      <valid>0:</valid>
+    </arg>
+  </function>
   <!-- http://man7.org/linux/man-pages/man3/scandir.3.html -->
   <!-- int scandir(const char *dirp, 
                     struct dirent ***namelist,
diff --git a/test/cfg/posix.c b/test/cfg/posix.c
index aad3c5f26..18c67233f 100644
--- a/test/cfg/posix.c
+++ b/test/cfg/posix.c
@@ -27,9 +27,18 @@
 #include <stdarg.h>
 #include <ctype.h>
 #include <stdbool.h>
+#define _XOPEN_SOURCE
 #include <wchar.h>
 #include <string.h>
 
+int nullPointer_wcswidth(const wchar_t *s, size_t n)
+{
+    // cppcheck-suppress nullPointer
+    (void)wcswidth(NULL, n);
+    // No warning is expected
+    return wcswidth(s, n);
+}
+
 int nullPointer_aio_cancel(int fd, struct aiocb *aiocbp)
 {
     // No warning is expected