[libunwind] a33d5a9 - [libunwind] Fflush stderr after each log message

[Martin Storsjö via cfe-commits]

Author: Martin Storsjö
Date: 2023-04-06T11:07:41+03:00
New Revision: a33d5a9939aa3c0bcdb0f951c0bc4b96071bda2c

URL: https://github.com/llvm/llvm-project/commit/a33d5a9939aa3c0bcdb0f951c0bc4b96071bda2c
DIFF: https://github.com/llvm/llvm-project/commit/a33d5a9939aa3c0bcdb0f951c0bc4b96071bda2c.diff

LOG: [libunwind] Fflush stderr after each log message

In most configs, stderr is line buffered by default, but in some
cases on Windows (running in git bash, or running in Wine) stderr
can end up fully buffered.

See 2ec75a0869ab01fa9caf310e8a31eb7716182d30 for a similar change
for the output from lit itself.

This has no effect on libunwind when the log messages aren't enabled
via the environment variables.

Differential Revision: https://reviews.llvm.org/D147632

Added: 
    

Modified: 
    libunwind/src/config.h

Removed: 
    


################################################################################
diff  --git a/libunwind/src/config.h b/libunwind/src/config.h
index 4bbac951624f9..6707d591361df 100644
--- a/libunwind/src/config.h
+++ b/libunwind/src/config.h
@@ -162,10 +162,14 @@
 #define _LIBUNWIND_LOG0(msg)
 #define _LIBUNWIND_LOG(msg, ...)
 #else
-#define _LIBUNWIND_LOG0(msg)                                               \
-  fprintf(stderr, "libunwind: " msg "\n")
-#define _LIBUNWIND_LOG(msg, ...)                                               \
-  fprintf(stderr, "libunwind: " msg "\n", __VA_ARGS__)
+#define _LIBUNWIND_LOG0(msg) do {                                              \
+    fprintf(stderr, "libunwind: " msg "\n");                                   \
+    fflush(stderr);                                                            \
+  } while (0)
+#define _LIBUNWIND_LOG(msg, ...) do {                                          \
+    fprintf(stderr, "libunwind: " msg "\n", __VA_ARGS__);                      \
+    fflush(stderr);                                                            \
+  } while (0)
 #endif
 
 #if defined(NDEBUG)