1 files changed, 4 insertions, 1 deletions

diff --git a/src/exceptionbase.cpp b/src/exceptionbase.cpp
index cea779d..9515e2d 100644
--- a/src/exceptionbase.cpp
+++ b/src/exceptionbase.cpp
@@ -55,7 +55,10 @@ void Bu::ExceptionBase::setWhat( const char *lpFormat, va_list &vargs )
         if( sWhat ) delete[] sWhat;
         int nSize;
 
-        nSize = vsnprintf( NULL, 0, lpFormat, vargs );
+        va_list vargs2;
+        va_copy( vargs2, vargs );
+        nSize = vsnprintf( NULL, 0, lpFormat, vargs2 );
+        va_end( vargs2 );
         sWhat = new char[nSize+1];
         vsnprintf( sWhat, nSize+1, lpFormat, vargs );
 }