[v4,32/54] tests/qtest: libqtest: Adapt global_qtest declaration for win32

Commit Message

Bin Meng Sept. 27, 2022, 11:06 a.m. UTC

From: Xuzhou Cheng <[e-mail]>

Commit dd2107497275 ("tests/libqtest: Use libqtest-single.h in tests that require global_qtest")
moved global_qtest to libqtest-single.h, by declaring global_qtest
attribute to be common and weak.

This trick unfortunately does not work on Windows, and building
qtest test cases results in multiple definition errors of the weak
symbol global_qtest, as Windows PE does not have the concept of
the so-called weak symbol like ELF in the *nix world.

However Windows does provide a trick to declare a variable to be
a common symbol, via __declspec(selectany) [1]. It does not provide
the "strong override weak" effect but we don't need it in our use
case anyway. So let's use it for win32.

[1] https://docs.microsoft.com/en-us/cpp/cpp/selectany

Signed-off-by: Xuzhou Cheng <[e-mail]>
Signed-off-by: Bin Meng <[e-mail]>
Reviewed-by: Thomas Huth <[e-mail]>
---

(no changes since v2)

Changes in v2:
- Use __declspec(selectany) for the common weak symbol on Windows

 tests/qtest/libqtest-single.h | 4 ++++
 1 file changed, 4 insertions(+)

Patch

diff --git a/tests/qtest/libqtest-single.h b/tests/qtest/libqtest-single.h
index 4e7d0ae1dc..851724cbcb 100644
--- a/tests/qtest/libqtest-single.h
+++ b/tests/qtest/libqtest-single.h
@@ -13,7 +13,11 @@ 
 
 #include "libqtest.h"
 
+#ifndef _WIN32
 QTestState *global_qtest __attribute__((common, weak));
+#else
+__declspec(selectany) QTestState *global_qtest;
+#endif
 
 /**
  * qtest_start: