[FFmpeg-devel] [PATCH] Made appropriate changes to be able to successfully build C++ files using a Visual C++ build on Windows

[Aaron Levinson]

>From 722cbb5f6544323430d883212ac2e38c4eb94e5f Mon Sep 17 00:00:00 2001
From: Aaron Levinson <alevinsn at aracnet.com>
Date: Wed, 12 Apr 2017 16:33:39 -0700
Subject: [PATCH] Made appropriate changes to be able to successfully build C++ files using a Visual C++ build on Windows.

Purpose:  Made appropriate changes to be able to
 successfully build C++ files using a Visual C++ build on Windows.  Note that
 this is a continuation of the "fixes w32pthreads to support C++" aspect of
 Kyle Schwarz's "Remove pthread dependency" patch that is available at
 https://patchwork.ffmpeg.org/patch/2654/ .  This patch wasn't accepted, and
 as far as I can tell, there was no follow-up after it was rejected.

Notes:  Used Visual Studio 2015 (with update 3) for this.

Comments:

-- compat/w32pthreads.h: Made appropriate changes to w32pthreads.h to
   get it to build when it is being included in a C++ file and built
   with Visual C++.  This is mostly a copy of Kyle Schwarz's patch as
   described above.

-- configure: Made minor modifications to MSVC (Microsoft Visual C++)
   toolchain section to make sure that -Fo$@ is used when building
   object files but when the C++ compiler is used and also to use cl
   for the default C++ compiler.  This is currently only relevant for
   building the Blackmagic/Decklink-related files under avdevice.
---
 compat/w32pthreads.h | 24 ++++++++++++------------
 configure            |  3 +++
 2 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/compat/w32pthreads.h b/compat/w32pthreads.h
index 0c9a7fa..a6c699b 100644
--- a/compat/w32pthreads.h
+++ b/compat/w32pthreads.h
@@ -77,7 +77,7 @@ typedef struct pthread_cond_t {
 
 static av_unused unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
 {
-    pthread_t *h = arg;
+    pthread_t *h = (pthread_t*)arg;
     h->ret = h->func(h->arg);
     return 0;
 }
@@ -270,7 +270,7 @@ static av_unused int pthread_cond_init(pthread_cond_t *cond, const void *unused_
     }
 
     /* non native condition variables */
-    win32_cond = av_mallocz(sizeof(win32_cond_t));
+    win32_cond = (win32_cond_t*)av_mallocz(sizeof(win32_cond_t));
     if (!win32_cond)
         return ENOMEM;
     cond->Ptr = win32_cond;
@@ -288,7 +288,7 @@ static av_unused int pthread_cond_init(pthread_cond_t *cond, const void *unused_
 
 static av_unused int pthread_cond_destroy(pthread_cond_t *cond)
 {
-    win32_cond_t *win32_cond = cond->Ptr;
+    win32_cond_t *win32_cond = (win32_cond_t*)cond->Ptr;
     /* native condition variables do not destroy */
     if (cond_init)
         return 0;
@@ -305,7 +305,7 @@ static av_unused int pthread_cond_destroy(pthread_cond_t *cond)
 
 static av_unused int pthread_cond_broadcast(pthread_cond_t *cond)
 {
-    win32_cond_t *win32_cond = cond->Ptr;
+    win32_cond_t *win32_cond = (win32_cond_t*)cond->Ptr;
     int have_waiter;
 
     if (cond_broadcast) {
@@ -337,7 +337,7 @@ static av_unused int pthread_cond_broadcast(pthread_cond_t *cond)
 
 static av_unused int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
 {
-    win32_cond_t *win32_cond = cond->Ptr;
+    win32_cond_t *win32_cond = (win32_cond_t*)cond->Ptr;
     int last_waiter;
     if (cond_wait) {
         cond_wait(cond, mutex, INFINITE);
@@ -369,7 +369,7 @@ static av_unused int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mu
 
 static av_unused int pthread_cond_signal(pthread_cond_t *cond)
 {
-    win32_cond_t *win32_cond = cond->Ptr;
+    win32_cond_t *win32_cond = (win32_cond_t*)cond->Ptr;
     int have_waiter;
     if (cond_signal) {
         cond_signal(cond);
@@ -400,17 +400,17 @@ static av_unused void w32thread_init(void)
     HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
     /* if one is available, then they should all be available */
     cond_init      = (void (WINAPI*)(pthread_cond_t *))
-        GetProcAddress(kernel_dll, "InitializeConditionVariable");
+        GetProcAddress((HMODULE)kernel_dll, "InitializeConditionVariable");
     cond_broadcast = (void (WINAPI*)(pthread_cond_t *))
-        GetProcAddress(kernel_dll, "WakeAllConditionVariable");
+        GetProcAddress((HMODULE)kernel_dll, "WakeAllConditionVariable");
     cond_signal    = (void (WINAPI*)(pthread_cond_t *))
-        GetProcAddress(kernel_dll, "WakeConditionVariable");
+        GetProcAddress((HMODULE)kernel_dll, "WakeConditionVariable");
     cond_wait      = (BOOL (WINAPI*)(pthread_cond_t *, pthread_mutex_t *, DWORD))
-        GetProcAddress(kernel_dll, "SleepConditionVariableCS");
+        GetProcAddress((HMODULE)kernel_dll, "SleepConditionVariableCS");
     initonce_begin = (BOOL (WINAPI*)(pthread_once_t *, DWORD, BOOL *, void **))
-        GetProcAddress(kernel_dll, "InitOnceBeginInitialize");
+        GetProcAddress((HMODULE)kernel_dll, "InitOnceBeginInitialize");
     initonce_complete = (BOOL (WINAPI*)(pthread_once_t *, DWORD, void *))
-        GetProcAddress(kernel_dll, "InitOnceComplete");
+        GetProcAddress((HMODULE)kernel_dll, "InitOnceComplete");
 #endif
 
 }
diff --git a/configure b/configure
index d13d60b..b0f7b1a 100755
--- a/configure
+++ b/configure
@@ -3635,10 +3635,13 @@ case "$toolchain" in
         # successfully parses the version number of existing supported
         # versions that require the converter (MSVC 2010 and 2012).
         cl_major_ver=$(cl 2>&1 | sed -n 's/.*Version \([[:digit:]]\{1,\}\)\..*/\1/p')
+        CXX_O='-Fo$@'
         if [ -z "$cl_major_ver" ] || [ $cl_major_ver -ge 18 ]; then
             cc_default="cl"
+            cxx_default="cl"
         else
             cc_default="c99wrap cl"
+            cxx_default="c99wrap cl"
         fi
         ld_default="$source_path/compat/windows/mslink"
         nm_default="dumpbin -symbols"
-- 
2.10.1.windows.1