diff --git a/include/qpdf/QUtil.hh b/include/qpdf/QUtil.hh
index 45dc9c5..d0626a2 100644
--- a/include/qpdf/QUtil.hh
+++ b/include/qpdf/QUtil.hh
@@ -52,6 +52,10 @@ namespace QUtil
     void binary_stdout();
     QPDF_DLL
     void binary_stdin();
+    // Set stdout to line buffered
+    QPDF_DLL
+    void setLineBuf(FILE*);
+
 
     // May modify argv0
     QPDF_DLL
diff --git a/libqpdf/QUtil.cc b/libqpdf/QUtil.cc
index bc81ce5..1bdae0f 100644
--- a/libqpdf/QUtil.cc
+++ b/libqpdf/QUtil.cc
@@ -127,6 +127,14 @@ QUtil::binary_stdin()
 #endif
 }
 
+void
+QUtil::setLineBuf(FILE* f)
+{
+#ifndef _WIN32
+    setvbuf(f, (char *) NULL, _IOLBF, 0);
+#endif
+}
+
 char*
 QUtil::getWhoami(char* argv0)
 {
diff --git a/qpdf/qpdf.cc b/qpdf/qpdf.cc
index f9af860..431f6da 100644
--- a/qpdf/qpdf.cc
+++ b/qpdf/qpdf.cc
@@ -534,7 +534,7 @@ parse_encrypt_options(
 int main(int argc, char* argv[])
 {
     whoami = QUtil::getWhoami(argv[0]);
-    setvbuf(stdout, (char *) NULL, _IOLBF, 0);
+    QUtil::setLineBuf(stdout);
 
     // For libtool's sake....
     if (strncmp(whoami, "lt-", 3) == 0)
diff --git a/qpdf/test_driver.cc b/qpdf/test_driver.cc
index 68866b5..f499891 100644
--- a/qpdf/test_driver.cc
+++ b/qpdf/test_driver.cc
@@ -320,7 +320,7 @@ void runtest(int n, char const* filename)
 
 int main(int argc, char* argv[])
 {
-    setvbuf(stdout, (char *) NULL, _IOLBF, 0);
+    QUtil::setLineBuf(stdout);
     if ((whoami = strrchr(argv[0], '/')) == NULL)
     {
 	whoami = argv[0];