Re: [PATCH v4 07/23] util: add API to fetch the current thread name

25 Sep 2025


      On Thu, Sep 25, 2025 at 10:44:25AM +0100, Daniel P. Berrangé wrote:
...
This will be used to include the thread name in error reports
in a later patch. It returns a const string stored in a thread
local to avoid memory allocation when it is called repeatedly
in a single thread. The thread name should be set at the very
start of the thread execution, which is the case when using
qemu_thread_create.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 include/qemu/thread.h    |  1 +
 meson.build              | 21 +++++++++++++++++
 util/qemu-thread-posix.c | 33 ++++++++++++++++++++++++++-
 util/qemu-thread-win32.c | 49 ++++++++++++++++++++++++++++++++++++----
 4 files changed, 99 insertions(+), 5 deletions(-)

...
+++ b/util/qemu-thread-posix.c
...
+const char *qemu_thread_get_name(void)
...
+# endif
+    if (rv != 0) {
+        strlcpy(namebuf, "unnamed", G_N_ELEMENTS(namebuf));
Should this be g_strlcpy() instead of strlcpy(), for consistency with
the Windows half of the patch, and since g_strlcpy() is much more
frequent in the QEMU codebase?
...
+++ b/util/qemu-thread-win32.c
...
@@ -38,14 +41,17 @@ static bool load_set_thread_description(void)
             SetThreadDescriptionFunc =
                 (pSetThreadDescription)GetProcAddress(kernel32_module,
                                                       "SetThreadDescription");
-            if (!SetThreadDescriptionFunc) {
+            GetThreadDescriptionFunc =
+                (pGetThreadDescription)GetProcAddress(kernel32_module,
+                                                      "GetThreadDescription");
+            if (!SetThreadDescriptionFunc || !GetThreadDescriptionFunc) {
                 FreeLibrary(kernel32_module);
             }
         }
         g_once_init_leave(&_init_once, 1);
     }
-    return !!SetThreadDescriptionFunc;
+    return !!(SetThreadDescriptionFunc && GetThreadDescriptionFunc);
Pre-patch, the !! was necessary for converting a pointer to a bool.
But && also converts to a bool, and "!!(bool)" is redundant compared
to just "bool".

But overall, the patch makes sense.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.
Virtualization:  qemu.org | libguestfs.org

    