diff --git a/programs/psa/psa_constant_names.c b/programs/psa/psa_constant_names.c
index 88821da..dd19677 100644
--- a/programs/psa/psa_constant_names.c
+++ b/programs/psa/psa_constant_names.c
@@ -4,6 +4,35 @@
 
 #include "psa/crypto.h"
 
+/* This block is present to support Visual Studio builds prior to 2015 */
+#if defined(_MSC_VER) && _MSC_VER < 1900
+#include <stdarg.h>
+int snprintf( char *s, size_t n, const char *fmt, ... )
+{
+    int ret;
+    va_list argp;
+
+    /* Avoid calling the invalid parameter handler by checking ourselves */
+    if( s == NULL || n == 0 || fmt == NULL )
+        return( -1 );
+
+    va_start( argp, fmt );
+#if defined(_TRUNCATE) && !defined(__MINGW32__)
+    ret = _vsnprintf_s( s, n, _TRUNCATE, fmt, argp );
+#else
+    ret = _vsnprintf( s, n, fmt, argp );
+    if( ret < 0 || (size_t) ret == n )
+    {
+        s[n-1] = '\0';
+        ret = -1;
+    }
+#endif
+    va_end( argp );
+
+    return( ret );
+}
+#endif
+
 /* There are different GET_HASH macros for different kinds of algorithms
  * built from hashes, but the values are all constructed on the
  * same model. */