[FFmpeg-devel] [PATCH] avcodec/get_bits: Avoid unused variable (PR #20843)

[mkver via ffmpeg-devel <ffmpeg-devel@ffmpeg.org>]

PR #20843 opened by mkver
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20843
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20843.patch

Fixes lots of warnings from MSVC (which does not support av_unused).


>From 338c2c6d4ad206e2da061e7baf7c30f005f0f380 Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Date: Wed, 5 Nov 2025 14:36:31 +0100
Subject: [PATCH] avcodec/get_bits: Avoid unused variable

Fixes lots of warnings from MSVC (which does not support av_unused).

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
---
 libavcodec/get_bits.h | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/libavcodec/get_bits.h b/libavcodec/get_bits.h
index 85c87c65b1..a0c0f51276 100644
--- a/libavcodec/get_bits.h
+++ b/libavcodec/get_bits.h
@@ -166,18 +166,22 @@ static inline unsigned int show_bits(GetBitContext *s, int n);
 
 #define MIN_CACHE_BITS 25
 
+#define OPEN_READER_NOSIZE_NOCACHE(name, gb)    \
+    unsigned int name ## _index = (gb)->index
+
 #define OPEN_READER_NOSIZE(name, gb)            \
-    unsigned int name ## _index = (gb)->index;  \
-    av_unused unsigned int name ## _cache
+    OPEN_READER_NOSIZE_NOCACHE(name, gb);       \
+    unsigned int name ## _cache
 
 #if UNCHECKED_BITSTREAM_READER
 #define OPEN_READER(name, gb) OPEN_READER_NOSIZE(name, gb)
-
+#define OPEN_READER_SIZE(name, gb) ((void)0)
 #define BITS_AVAILABLE(name, gb) 1
 #else
+#define OPEN_READER_SIZE(name, gb) unsigned int name ## _size_plus8 = (gb)->size_in_bits_plus8
 #define OPEN_READER(name, gb)                   \
     OPEN_READER_NOSIZE(name, gb);               \
-    unsigned int name ## _size_plus8 = (gb)->size_in_bits_plus8
+    OPEN_READER_SIZE(name, gb)
 
 #define BITS_AVAILABLE(name, gb) name ## _index < name ## _size_plus8
 #endif
@@ -378,7 +382,8 @@ static inline unsigned int show_bits(GetBitContext *s, int n)
 
 static inline void skip_bits(GetBitContext *s, int n)
 {
-    OPEN_READER(re, s);
+    OPEN_READER_NOSIZE_NOCACHE(re, s);
+    OPEN_READER_SIZE(re, s);
     LAST_SKIP_BITS(re, s, n);
     CLOSE_READER(re, s);
 }
-- 
2.49.1

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