Workaround Uplink compilation for MINGW 32bit

The uplink code breaks compilation with strict warnings
for MINGW (only for 32-bit).
  error: ISO C forbids conversion of object pointer
  to function pointer type [-Werror=pedantic]
or
  error: ISO C forbids assignment between function pointer
  and 'void *' [-Werror=pedantic]

and some other missing declarations and prototypes.

As uplink.h is included in cryptlib.h and used in BIO
code, using a pragma to disable warnings would touch
to much code.

With (uintptr_t) cast, it silences cast warnings with gcc.

For the rest of the code, just disable warnings, as this
code would need to be rewritten and heavily retested
on older systems.
NOTE: applink.c is INCLUDED from uplink.h.

Reviewed-by: Nikola Pajkovsky <nikolap@openssl.org>
Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Norbert Pocs <norbertp@openssl.org>
MergeDate: Tue Apr 28 16:02:22 2026
(Merged from https://github.com/openssl/openssl/pull/30963)

ms/applink.c

@@ -35,6 +35,12 @@
 
 #ifndef APPMACROS_ONLY
 
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpedantic"
+#pragma GCC diagnostic ignored "-Wmissing-prototypes"
+#endif
+
 /*
  * Normally, do not define APPLINK_NO_INCLUDES.  Define it if you are using
  * symbol preprocessing and do not want the preprocessing to affect the
@@ -145,6 +151,10 @@ __declspec(dllexport) void **
     return OPENSSL_ApplinkTable;
 }
 
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
+
 #ifdef __cplusplus
 }
 #endif

ms/uplink.c

@@ -17,12 +17,19 @@
 #define UNICODE
 #endif
 
+#ifdef __GNUC__
+#pragma GCC diagnostic ignored "-Wpedantic"
+#pragma GCC diagnostic ignored "-Wcast-function-type"
+#pragma GCC diagnostic ignored "-Wstrict-prototypes"
+#endif
+
 #include <windows.h>
 #include <tchar.h>
 #include <stdio.h>
 #include <stddef.h>
 #include "uplink.h"
 void OPENSSL_showfatal(const char *, ...);
+void OPENSSL_Uplink(volatile void **table, int index);
 
 static TCHAR msg[128];
 
@@ -73,7 +80,6 @@ void OPENSSL_Uplink(volatile void **table, int index)
 
         if (applinktable == NULL) {
             void **(*applink)();
-
             applink = (void **(*)())GetProcAddress(h, "OPENSSL_Applink");
             if (applink == NULL) {
                 apphandle = (HMODULE)-1;

ms/uplink.h

@@ -12,27 +12,27 @@
 
 extern void *OPENSSL_UplinkTable[];
 
-#define UP_stdin (*(void *(*)(void))OPENSSL_UplinkTable[APPLINK_STDIN])()
-#define UP_stdout (*(void *(*)(void))OPENSSL_UplinkTable[APPLINK_STDOUT])()
-#define UP_stderr (*(void *(*)(void))OPENSSL_UplinkTable[APPLINK_STDERR])()
-#define UP_fprintf (*(int (*)(void *, const char *, ...))OPENSSL_UplinkTable[APPLINK_FPRINTF])
-#define UP_fgets (*(char *(*)(char *, int, void *))OPENSSL_UplinkTable[APPLINK_FGETS])
-#define UP_fread (*(size_t (*)(void *, size_t, size_t, void *))OPENSSL_UplinkTable[APPLINK_FREAD])
-#define UP_fwrite (*(size_t (*)(const void *, size_t, size_t, void *))OPENSSL_UplinkTable[APPLINK_FWRITE])
-#define UP_fsetmod (*(int (*)(void *, char))OPENSSL_UplinkTable[APPLINK_FSETMOD])
-#define UP_feof (*(int (*)(void *))OPENSSL_UplinkTable[APPLINK_FEOF])
-#define UP_fclose (*(int (*)(void *))OPENSSL_UplinkTable[APPLINK_FCLOSE])
+#define UP_stdin (*(void *(*)(void))(uintptr_t)OPENSSL_UplinkTable[APPLINK_STDIN])()
+#define UP_stdout (*(void *(*)(void))(uintptr_t)OPENSSL_UplinkTable[APPLINK_STDOUT])()
+#define UP_stderr (*(void *(*)(void))(uintptr_t)OPENSSL_UplinkTable[APPLINK_STDERR])()
+#define UP_fprintf (*(int (*)(void *, const char *, ...))(uintptr_t)OPENSSL_UplinkTable[APPLINK_FPRINTF])
+#define UP_fgets (*(char *(*)(char *, int, void *))(uintptr_t)OPENSSL_UplinkTable[APPLINK_FGETS])
+#define UP_fread (*(size_t (*)(void *, size_t, size_t, void *))(uintptr_t)OPENSSL_UplinkTable[APPLINK_FREAD])
+#define UP_fwrite (*(size_t (*)(const void *, size_t, size_t, void *))(uintptr_t)OPENSSL_UplinkTable[APPLINK_FWRITE])
+#define UP_fsetmod (*(int (*)(void *, char))(uintptr_t)OPENSSL_UplinkTable[APPLINK_FSETMOD])
+#define UP_feof (*(int (*)(void *))(uintptr_t)OPENSSL_UplinkTable[APPLINK_FEOF])
+#define UP_fclose (*(int (*)(void *))(uintptr_t)OPENSSL_UplinkTable[APPLINK_FCLOSE])
 
-#define UP_fopen (*(void *(*)(const char *, const char *))OPENSSL_UplinkTable[APPLINK_FOPEN])
-#define UP_fseek (*(int (*)(void *, long, int))OPENSSL_UplinkTable[APPLINK_FSEEK])
-#define UP_ftell (*(long (*)(void *))OPENSSL_UplinkTable[APPLINK_FTELL])
-#define UP_fflush (*(int (*)(void *))OPENSSL_UplinkTable[APPLINK_FFLUSH])
-#define UP_ferror (*(int (*)(void *))OPENSSL_UplinkTable[APPLINK_FERROR])
-#define UP_clearerr (*(void (*)(void *))OPENSSL_UplinkTable[APPLINK_CLEARERR])
-#define UP_fileno (*(int (*)(void *))OPENSSL_UplinkTable[APPLINK_FILENO])
+#define UP_fopen (*(void *(*)(const char *, const char *))(uintptr_t)OPENSSL_UplinkTable[APPLINK_FOPEN])
+#define UP_fseek (*(int (*)(void *, long, int))(uintptr_t)OPENSSL_UplinkTable[APPLINK_FSEEK])
+#define UP_ftell (*(long (*)(void *))(uintptr_t)OPENSSL_UplinkTable[APPLINK_FTELL])
+#define UP_fflush (*(int (*)(void *))(uintptr_t)OPENSSL_UplinkTable[APPLINK_FFLUSH])
+#define UP_ferror (*(int (*)(void *))(uintptr_t)OPENSSL_UplinkTable[APPLINK_FERROR])
+#define UP_clearerr (*(void (*)(void *))(uintptr_t)OPENSSL_UplinkTable[APPLINK_CLEARERR])
+#define UP_fileno (*(int (*)(void *))(uintptr_t)OPENSSL_UplinkTable[APPLINK_FILENO])
 
-#define UP_open (*(int (*)(const char *, int, ...))OPENSSL_UplinkTable[APPLINK_OPEN])
-#define UP_read (*(ossl_ssize_t (*)(int, void *, size_t))OPENSSL_UplinkTable[APPLINK_READ])
-#define UP_write (*(ossl_ssize_t (*)(int, const void *, size_t))OPENSSL_UplinkTable[APPLINK_WRITE])
-#define UP_lseek (*(long (*)(int, long, int))OPENSSL_UplinkTable[APPLINK_LSEEK])
-#define UP_close (*(int (*)(int))OPENSSL_UplinkTable[APPLINK_CLOSE])
+#define UP_open (*(int (*)(const char *, int, ...))(uintptr_t)OPENSSL_UplinkTable[APPLINK_OPEN])
+#define UP_read (*(ossl_ssize_t (*)(int, void *, size_t))(uintptr_t)OPENSSL_UplinkTable[APPLINK_READ])
+#define UP_write (*(ossl_ssize_t (*)(int, const void *, size_t))(uintptr_t)OPENSSL_UplinkTable[APPLINK_WRITE])
+#define UP_lseek (*(long (*)(int, long, int))(uintptr_t)OPENSSL_UplinkTable[APPLINK_LSEEK])
+#define UP_close (*(int (*)(int))(uintptr_t)OPENSSL_UplinkTable[APPLINK_CLOSE])