diff --git a/src/libCom/osi/os/posix/epicsStdio.cpp b/src/libCom/osi/os/posix/epicsStdio.cpp
index 3167166c1..0933b4f4f 100644
--- a/src/libCom/osi/os/posix/epicsStdio.cpp
+++ b/src/libCom/osi/os/posix/epicsStdio.cpp
@@ -15,13 +15,13 @@ extern "C" {
 epicsShareFunc int epicsShareAPI epicsSnprintf(
     char *str, size_t size, const char *format, ...)
 {
-    return vsnprintf ( str, size, format );
+    return snprintf ( str, size, format );
 }
 
 epicsShareFunc int epicsShareAPI epicsVsnprintf(
     char *str, size_t size, const char *format, va_list ap)
 {
-    return snprintf ( str, size, format, ap );
+    return vsnprintf ( str, size, format, ap );
 }
 
 }