[PATCH] [libiberty] PR other/108662 Replace explicit linking to GlobalMemoryStatusEx() with implicit linking

[Jan Dubiec]

On Windows this patch replaces explicit linking (aka run-time dynamic
linking) to GlobalMemoryStatusEx() with implicit linking. It also
simplifies the code and gets rid of annoying "cast between incompatible
function types" message. According to Microsoft GlobalMemoryStatusEx()
requires at least Windows XP[1] so fossils like Windows 9x or even
Windows 2000 are not supported. Although I think we should not care
about them taking into account that even some systems newer than XP are
not supported by Microsoft itself.
[1] 
https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-globalmemorystatusex

2025-06-23  Jan Dubiec  <j...@o2.pl>

        PR other/108662

libiberty/ChangeLog:

        * physmem.c: Replace explicit linking to GlobalMemoryStatusEx()
        with implicit linking and get rid of annoying "cast between
        incompatible function types" message.
 libiberty/physmem.c | 69 +++++++----------------------------------------------
 1 file changed, 8 insertions(+), 61 deletions(-)

diff --git a/libiberty/physmem.c b/libiberty/physmem.c
index 62253e120e2..c6976efde8c 100644
--- a/libiberty/physmem.c
+++ b/libiberty/physmem.c
@@ -59,21 +59,6 @@
 #ifdef _WIN32
 # define WIN32_LEAN_AND_MEAN
 # include <windows.h>
-/*  MEMORYSTATUSEX is missing from older windows headers, so define
-    a local replacement.  */
-typedef struct
-{
-  DWORD dwLength;
-  DWORD dwMemoryLoad;
-  DWORDLONG ullTotalPhys;
-  DWORDLONG ullAvailPhys;
-  DWORDLONG ullTotalPageFile;
-  DWORDLONG ullAvailPageFile;
-  DWORDLONG ullTotalVirtual;
-  DWORDLONG ullAvailVirtual;
-  DWORDLONG ullAvailExtendedVirtual;
-} lMEMORYSTATUSEX;
-typedef WINBOOL (WINAPI *PFN_MS_EX) (lMEMORYSTATUSEX*);
 #endif
 
 #include "libiberty.h"
@@ -151,30 +136,11 @@ physmem_total (void)
 
 #if defined _WIN32
   { /* this works on windows */
-    PFN_MS_EX pfnex;
-    HMODULE h = GetModuleHandle ("kernel32.dll");
-
-    if (!h)
+    MEMORYSTATUSEX ms_ex;
+    ms_ex.dwLength = sizeof ms_ex;
+    if (!GlobalMemoryStatusEx (&ms_ex))
       return 0.0;
-
-    /*  Use GlobalMemoryStatusEx if available.  */
-    if ((pfnex = (PFN_MS_EX) GetProcAddress (h, "GlobalMemoryStatusEx")))
-      {
-       lMEMORYSTATUSEX lms_ex;
-       lms_ex.dwLength = sizeof lms_ex;
-       if (!pfnex (&lms_ex))
-         return 0.0;
-       return (double) lms_ex.ullTotalPhys;
-      }
-
-    /*  Fall back to GlobalMemoryStatus which is always available.
-        but returns wrong results for physical memory > 4GB.  */
-    else
-      {
-       MEMORYSTATUS ms;
-       GlobalMemoryStatus (&ms);
-       return (double) ms.dwTotalPhys;
-      }
+    return (double) ms_ex.ullTotalPhys;
   }
 #endif
 
@@ -252,30 +218,11 @@ physmem_available (void)
 
 #if defined _WIN32
   { /* this works on windows */
-    PFN_MS_EX pfnex;
-    HMODULE h = GetModuleHandle ("kernel32.dll");
-
-    if (!h)
+    MEMORYSTATUSEX ms_ex;
+    ms_ex.dwLength = sizeof ms_ex;
+    if (!GlobalMemoryStatusEx (&ms_ex))
       return 0.0;
-
-    /*  Use GlobalMemoryStatusEx if available.  */
-    if ((pfnex = (PFN_MS_EX) GetProcAddress (h, "GlobalMemoryStatusEx")))
-      {
-       lMEMORYSTATUSEX lms_ex;
-       lms_ex.dwLength = sizeof lms_ex;
-       if (!pfnex (&lms_ex))
-         return 0.0;
-       return (double) lms_ex.ullAvailPhys;
-      }
-
-    /*  Fall back to GlobalMemoryStatus which is always available.
-        but returns wrong results for physical memory > 4GB  */
-    else
-      {
-       MEMORYSTATUS ms;
-       GlobalMemoryStatus (&ms);
-       return (double) ms.dwAvailPhys;
-      }
+    return (double) ms_ex.ullAvailPhys;
   }
 #endif