diff --git a/phreeqcpp/Phreeqc.h b/phreeqcpp/Phreeqc.h
index c3f20aae..31d8c98f 100644
--- a/phreeqcpp/Phreeqc.h
+++ b/phreeqcpp/Phreeqc.h
@@ -2081,3 +2081,43 @@ char* _string_duplicate(const char* token, const char* szFileName, int nLine);
 #endif
 
 #endif //_INC_UTILITIES_NAMESPACE_H
+
+#ifndef _INC_MISSING_SNPRINTF_H
+#define _INC_MISSING_SNPRINTF_H
+
+// Section _INC_MISSING_SNPRINTF_H is based on
+// https://stackoverflow.com/questions/2915672/snprintf-and-visual-studio-2010
+
+#if defined(_MSC_VER) && (_MSC_VER < 1900)
+
+#include <stdarg.h>
+
+#define snprintf c99_snprintf
+#define vsnprintf c99_vsnprintf
+
+__inline int c99_vsnprintf(char *outBuf, size_t size, const char *format, va_list ap)
+{
+    int count = -1;
+
+    if (size != 0)
+        count = _vsnprintf_s(outBuf, size, _TRUNCATE, format, ap);
+    if (count == -1)
+        count = _vscprintf(format, ap);
+
+    return count;
+}
+
+__inline int c99_snprintf(char *outBuf, size_t size, const char *format, ...)
+{
+    int count;
+    va_list ap;
+
+    va_start(ap, format);
+    count = c99_vsnprintf(outBuf, size, format, ap);
+    va_end(ap);
+
+    return count;
+}
+#endif // defined(_MSC_VER) && (_MSC_VER < 1900)
+
+#endif //_INC_MISSING_SNPRINTF_H