Hi Bruno,
On 5/24/24 4:44 AM, Bruno Haible wrote:
> The longer the API is available, the better. Gnulib supports
> Windows XP as the minimum. For modules used by Emacs ('boot-time' in
> particular) it should run even on Windows 2000.
>
> Which means that the code needs to fetch a pointer to the particular
> Windows API function at runtime, through GetProcAddress. See lib/isatty.c
> as an example.
>
> Would you like to give it a try?
I wrote this patch just now. Any thoughts?
I've only tested it with a mingw compiler and wine so far.
I wasn't sure the proper way to get the current time. I didn't want to
depend on timespec_get since that would bring in more dependencies for
non-Windows systems (like linking with -lrt). The resolution isn't
needed either since GetTickCount64 has a resolution of 10-16 ms [1].
I suppose a Native Windows function would do fine, but I am not
familiar with the API. I presume that is the case for most others too.
Therefore I think gettimeofday makes sense since most systems should
just have it.
[1]
https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-gettickcount64#remarks
Collin
From acd118c0057f206f212cb45000aa852cfb083af6 Mon Sep 17 00:00:00 2001
From: Collin Funk <collin.fu...@gmail.com>
Date: Fri, 24 May 2024 14:07:26 -0700
Subject: [PATCH] boot-time: Add a fallback function for Windows.
* lib/boot-time-aux.h (initialize, get_windows_boot_time_fallback): New
functions.
* lib/boot-time.c [_WIN32]: Include Windows headers and sys/time.h.
(get_boot_time_uncached): Use the new Windows fallback.
* modules/boot-time (Depends-on): Add gettimeofday.
---
ChangeLog | 9 ++++++
lib/boot-time-aux.h | 72 +++++++++++++++++++++++++++++++++++++++++++++
lib/boot-time.c | 9 ++++++
modules/boot-time | 1 +
4 files changed, 91 insertions(+)
diff --git a/ChangeLog b/ChangeLog
index d9112a810a..b26fe146f4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2024-05-24 Collin Funk <collin.fu...@gmail.com>
+
+ boot-time: Add a fallback function for Windows.
+ * lib/boot-time-aux.h (initialize, get_windows_boot_time_fallback): New
+ functions.
+ * lib/boot-time.c [_WIN32]: Include Windows headers and sys/time.h.
+ (get_boot_time_uncached): Use the new Windows fallback.
+ * modules/boot-time (Depends-on): Add gettimeofday.
+
2024-05-24 Bruno Haible <br...@clisp.org>
putenv tests: Put the putenv() argument strings into writable memory.
diff --git a/lib/boot-time-aux.h b/lib/boot-time-aux.h
index b1add30239..e51c58ff6f 100644
--- a/lib/boot-time-aux.h
+++ b/lib/boot-time-aux.h
@@ -345,4 +345,76 @@ get_windows_boot_time (struct timespec *p_boot_time)
return -1;
}
+# if !(_WIN32_WINNT >= _WIN32_WINNT_VISTA)
+
+/* Don't assume that UNICODE is not defined. */
+# undef LoadLibrary
+# define LoadLibrary LoadLibraryA
+
+/* Avoid warnings from gcc -Wcast-function-type. */
+# define GetProcAddress \
+ (void *) GetProcAddress
+
+/* GetTickCount64 is only available on Windows Vista and later. */
+typedef ULONGLONG (WINAPI * GetTickCount64FuncType) (void);
+
+static GetTickCount64FuncType GetTickCount64Func = NULL;
+static BOOL initialized = FALSE;
+
+static void
+initialize (void)
+{
+ HMODULE kernel32 = LoadLibrary ("kernel32.dll");
+ if (kernel32 != NULL)
+ {
+ GetTickCount64Func =
+ (GetTickCount64FuncType) GetProcAddress (kernel32, "GetTickCount64");
+ }
+ initialized = TRUE;
+}
+
+# else
+
+# define GetTickCount64Func GetTickCount64
+
+# endif
+
+/* Fallback for Windows in the form:
+ boot time = current time - uptime
+ This uses the GetTickCount64 function which is only available on Windows
+ Vista and later. See:
+ <https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-gettickcount64>. */
+static int
+get_windows_boot_time_fallback (struct timespec *p_boot_time)
+{
+# if !(_WIN32_WINNT >= _WIN32_WINNT_VISTA)
+ if (! initialized)
+ initialize ();
+#endif
+ if (GetTickCount64Func != NULL)
+ {
+ ULONGLONG uptime_ms = GetTickCount64Func ();
+ struct timespec uptime;
+ struct timespec result;
+ struct timeval tv;
+ if (gettimeofday (&tv, NULL) >= 0)
+ {
+ uptime.tv_sec = uptime_ms / 1000;
+ uptime.tv_nsec = (uptime_ms % 1000) * 1000000;
+ result.tv_sec = tv.tv_sec;
+ result.tv_nsec = tv.tv_usec * 1000;
+ if (result.tv_nsec < uptime.tv_nsec)
+ {
+ result.tv_nsec += 1000000000;
+ result.tv_sec -= 1;
+ }
+ result.tv_sec -= uptime.tv_sec;
+ result.tv_nsec -= uptime.tv_nsec;
+ *p_boot_time = result;
+ return 0;
+ }
+ }
+ return -1;
+}
+
#endif
diff --git a/lib/boot-time.c b/lib/boot-time.c
index c1171e8024..c0a8ea6903 100644
--- a/lib/boot-time.c
+++ b/lib/boot-time.c
@@ -43,6 +43,13 @@
# include <OS.h>
#endif
+#ifdef _WIN32
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+# include <sysinfoapi.h>
+# include <sys/time.h>
+#endif
+
#include "idx.h"
#include "readutmp.h"
#include "stat-time.h"
@@ -247,6 +254,8 @@ get_boot_time_uncached (struct timespec *p_boot_time)
{
/* Workaround for Windows: */
get_windows_boot_time (&found_boot_time);
+ if (found_boot_time.tv_sec == 0)
+ get_windows_boot_time_fallback (&found_boot_time);
}
# endif
diff --git a/modules/boot-time b/modules/boot-time
index 2d89969d5c..07e5e43bc6 100644
--- a/modules/boot-time
+++ b/modules/boot-time
@@ -12,6 +12,7 @@ Depends-on:
extensions
idx
stat-time
+gettimeofday
stdbool
time-h
unlocked-io-internal
--
2.45.1
