[Xen-devel] [PATCH v2 2/8] tools/livepatch: Set stdout and stderr unbuffered

[Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>]

Using both stdout and stderr interleaved without newlines can result in
strange output when using line buffered mode (e.g. a terminal) or when
fully buffered (e.g. redirected to a file). Set stdout to unbuffered mode
to fix this (stderr is always unbuffered by default).

Signed-off-by: Ross Lagerwall <ross.lagerwall@xxxxxxxxxx>
---
 tools/misc/xen-livepatch.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/tools/misc/xen-livepatch.c b/tools/misc/xen-livepatch.c
index f6c7c8a..56ae5aa 100644
--- a/tools/misc/xen-livepatch.c
+++ b/tools/misc/xen-livepatch.c
@@ -330,7 +330,6 @@ int action_func(int argc, char *argv[], unsigned int idx)
         }
 
         printf(".");
-        fflush(stdout);
         usleep(DELAY);
     } while ( ++retry < RETRIES );
 
@@ -416,6 +415,12 @@ int main(int argc, char *argv[])
 {
     int i, j = 0, ret;
 
+    /*
+     * Set stdout to be unbuffered to avoid having to fflush when
+     * printing without a newline.
+     */
+    setvbuf(stdout, NULL, _IONBF, 0);
+
     if ( argc  <= 1 )
     {
         show_help();
-- 
2.7.4


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