diff --git a/src/Log.cxx b/src/Log.cxx
index 41e4958bc..21fcdefb8 100644
--- a/src/Log.cxx
+++ b/src/Log.cxx
@@ -30,7 +30,7 @@ static constexpr Domain exception_domain("exception");
 
 void
 LogFormatV(LogLevel level, const Domain &domain,
-	   const char *fmt, va_list ap) noexcept
+	   const char *fmt, std::va_list ap) noexcept
 {
 	char msg[1024];
 	vsnprintf(msg, sizeof(msg), fmt, ap);
@@ -40,7 +40,7 @@ LogFormatV(LogLevel level, const Domain &domain,
 void
 LogFormat(LogLevel level, const Domain &domain, const char *fmt, ...) noexcept
 {
-	va_list ap;
+	std::va_list ap;
 	va_start(ap, fmt);
 	LogFormatV(level, domain, fmt, ap);
 	va_end(ap);
@@ -49,7 +49,7 @@ LogFormat(LogLevel level, const Domain &domain, const char *fmt, ...) noexcept
 void
 FormatDebug(const Domain &domain, const char *fmt, ...) noexcept
 {
-	va_list ap;
+	std::va_list ap;
 	va_start(ap, fmt);
 	LogFormatV(LogLevel::DEBUG, domain, fmt, ap);
 	va_end(ap);
@@ -58,7 +58,7 @@ FormatDebug(const Domain &domain, const char *fmt, ...) noexcept
 void
 FormatInfo(const Domain &domain, const char *fmt, ...) noexcept
 {
-	va_list ap;
+	std::va_list ap;
 	va_start(ap, fmt);
 	LogFormatV(LogLevel::INFO, domain, fmt, ap);
 	va_end(ap);
@@ -67,7 +67,7 @@ FormatInfo(const Domain &domain, const char *fmt, ...) noexcept
 void
 FormatDefault(const Domain &domain, const char *fmt, ...) noexcept
 {
-	va_list ap;
+	std::va_list ap;
 	va_start(ap, fmt);
 	LogFormatV(LogLevel::DEFAULT, domain, fmt, ap);
 	va_end(ap);
@@ -76,7 +76,7 @@ FormatDefault(const Domain &domain, const char *fmt, ...) noexcept
 void
 FormatWarning(const Domain &domain, const char *fmt, ...) noexcept
 {
-	va_list ap;
+	std::va_list ap;
 	va_start(ap, fmt);
 	LogFormatV(LogLevel::WARNING, domain, fmt, ap);
 	va_end(ap);
@@ -85,7 +85,7 @@ FormatWarning(const Domain &domain, const char *fmt, ...) noexcept
 void
 FormatError(const Domain &domain, const char *fmt, ...) noexcept
 {
-	va_list ap;
+	std::va_list ap;
 	va_start(ap, fmt);
 	LogFormatV(LogLevel::ERROR, domain, fmt, ap);
 	va_end(ap);
@@ -107,7 +107,7 @@ void
 LogFormat(LogLevel level, const std::exception &e, const char *fmt, ...) noexcept
 {
 	char msg[1024];
-	va_list ap;
+	std::va_list ap;
 	va_start(ap, fmt);
 	vsnprintf(msg, sizeof(msg), fmt, ap);
 	va_end(ap);
@@ -132,7 +132,7 @@ void
 LogFormat(LogLevel level, const std::exception_ptr &ep, const char *fmt, ...) noexcept
 {
 	char msg[1024];
-	va_list ap;
+	std::va_list ap;
 	va_start(ap, fmt);
 	vsnprintf(msg, sizeof(msg), fmt, ap);
 	va_end(ap);
@@ -153,7 +153,7 @@ LogErrno(const Domain &domain, const char *msg) noexcept
 }
 
 static void
-FormatErrnoV(const Domain &domain, int e, const char *fmt, va_list ap) noexcept
+FormatErrnoV(const Domain &domain, int e, const char *fmt, std::va_list ap) noexcept
 {
 	char msg[1024];
 	vsnprintf(msg, sizeof(msg), fmt, ap);
@@ -164,7 +164,7 @@ FormatErrnoV(const Domain &domain, int e, const char *fmt, va_list ap) noexcept
 void
 FormatErrno(const Domain &domain, int e, const char *fmt, ...) noexcept
 {
-	va_list ap;
+	std::va_list ap;
 	va_start(ap, fmt);
 	FormatErrnoV(domain, e, fmt, ap);
 	va_end(ap);
@@ -175,7 +175,7 @@ FormatErrno(const Domain &domain, const char *fmt, ...) noexcept
 {
 	const int e = errno;
 
-	va_list ap;
+	std::va_list ap;
 	va_start(ap, fmt);
 	FormatErrnoV(domain, e, fmt, ap);
 	va_end(ap);
diff --git a/src/LogV.hxx b/src/LogV.hxx
index 493f47d12..64ae193c8 100644
--- a/src/LogV.hxx
+++ b/src/LogV.hxx
@@ -22,10 +22,10 @@
 
 #include "Log.hxx" // IWYU pragma: export
 
-#include <stdarg.h>
+#include <cstdarg>
 
 void
 LogFormatV(LogLevel level, const Domain &domain,
-	   const char *fmt, va_list ap) noexcept;
+	   const char *fmt, std::va_list ap) noexcept;
 
 #endif /* LOG_H */
diff --git a/src/android/LogListener.cxx b/src/android/LogListener.cxx
index 8e89f2129..a6156033d 100644
--- a/src/android/LogListener.cxx
+++ b/src/android/LogListener.cxx
@@ -36,7 +36,7 @@ LogListener::OnLog(JNIEnv *env, int priority,
 
 	assert(method);
 
-	va_list args;
+	std::va_list args;
 	va_start(args, fmt);
 	const auto log = FormatStringV(fmt, args);
 	va_end(args);
diff --git a/src/client/Response.cxx b/src/client/Response.cxx
index 207489fa6..7c8118e6f 100644
--- a/src/client/Response.cxx
+++ b/src/client/Response.cxx
@@ -41,7 +41,7 @@ Response::Write(const char *data) noexcept
 }
 
 bool
-Response::FormatV(const char *fmt, va_list args) noexcept
+Response::FormatV(const char *fmt, std::va_list args) noexcept
 {
 	return Write(FormatStringV(fmt, args).c_str());
 }
@@ -49,7 +49,7 @@ Response::FormatV(const char *fmt, va_list args) noexcept
 bool
 Response::Format(const char *fmt, ...) noexcept
 {
-	va_list args;
+	std::va_list args;
 	va_start(args, fmt);
 	bool success = FormatV(fmt, args);
 	va_end(args);
@@ -78,7 +78,7 @@ Response::FormatError(enum ack code, const char *fmt, ...) noexcept
 	Format("ACK [%i@%u] {%s} ",
 	       (int)code, list_index, command);
 
-	va_list args;
+	std::va_list args;
 	va_start(args, fmt);
 	FormatV(fmt, args);
 	va_end(args);
diff --git a/src/client/Response.hxx b/src/client/Response.hxx
index f5898b16b..b2c72cf48 100644
--- a/src/client/Response.hxx
+++ b/src/client/Response.hxx
@@ -23,8 +23,9 @@
 #include "protocol/Ack.hxx"
 #include "util/Compiler.h"
 
+#include <cstdarg>
+
 #include <stddef.h>
-#include <stdarg.h>
 
 template<typename T> struct ConstBuffer;
 class Client;
@@ -74,7 +75,7 @@ public:
 
 	bool Write(const void *data, size_t length) noexcept;
 	bool Write(const char *data) noexcept;
-	bool FormatV(const char *fmt, va_list args) noexcept;
+	bool FormatV(const char *fmt, std::va_list args) noexcept;
 	bool Format(const char *fmt, ...) noexcept;
 
 	static constexpr size_t MAX_BINARY_SIZE = 8192;
diff --git a/src/fs/io/BufferedOutputStream.cxx b/src/fs/io/BufferedOutputStream.cxx
index 46249de0a..eb0d2d804 100644
--- a/src/fs/io/BufferedOutputStream.cxx
+++ b/src/fs/io/BufferedOutputStream.cxx
@@ -30,7 +30,8 @@
 #include "BufferedOutputStream.hxx"
 #include "OutputStream.hxx"
 
-#include <stdarg.h>
+#include <cstdarg>
+
 #include <string.h>
 #include <stdio.h>
 
@@ -85,7 +86,7 @@ BufferedOutputStream::Format(const char *fmt, ...)
 	}
 
 	/* format into the buffer */
-	va_list ap;
+	std::va_list ap;
 	va_start(ap, fmt);
 	size_t size = vsnprintf(r.data, r.size, fmt, ap);
 	va_end(ap);
diff --git a/src/lib/ffmpeg/LogCallback.cxx b/src/lib/ffmpeg/LogCallback.cxx
index 1e9bc3d99..d88f298d0 100644
--- a/src/lib/ffmpeg/LogCallback.cxx
+++ b/src/lib/ffmpeg/LogCallback.cxx
@@ -47,7 +47,7 @@ FfmpegImportLogLevel(int level) noexcept
 }
 
 void
-FfmpegLogCallback(gcc_unused void *ptr, int level, const char *fmt, va_list vl)
+FfmpegLogCallback(gcc_unused void *ptr, int level, const char *fmt, std::va_list vl)
 {
 	const AVClass * cls = nullptr;
 
diff --git a/src/lib/ffmpeg/LogCallback.hxx b/src/lib/ffmpeg/LogCallback.hxx
index 08d8d2251..0896ea2f2 100644
--- a/src/lib/ffmpeg/LogCallback.hxx
+++ b/src/lib/ffmpeg/LogCallback.hxx
@@ -20,9 +20,9 @@
 #ifndef MPD_FFMPEG_LOG_CALLBACK_HXX
 #define MPD_FFMPEG_LOG_CALLBACK_HXX
 
-#include <stdarg.h>
+#include <cstdarg>
 
 void
-FfmpegLogCallback(void *ptr, int level, const char *fmt, va_list vl);
+FfmpegLogCallback(void *ptr, int level, const char *fmt, std::va_list vl);
 
 #endif
diff --git a/src/system/FatalError.cxx b/src/system/FatalError.cxx
index 7e195a7d2..f3e8b6e0c 100644
--- a/src/system/FatalError.cxx
+++ b/src/system/FatalError.cxx
@@ -21,8 +21,9 @@
 #include "util/Domain.hxx"
 #include "LogV.hxx"
 
+#include <cstdarg>
+
 #include <unistd.h>
-#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -52,7 +53,7 @@ FatalError(const char *msg)
 void
 FormatFatalError(const char *fmt, ...)
 {
-	va_list ap;
+	std::va_list ap;
 	va_start(ap, fmt);
 	LogFormatV(LogLevel::ERROR, fatal_error_domain, fmt, ap);
 	va_end(ap);
@@ -91,7 +92,7 @@ void
 FormatFatalSystemError(const char *fmt, ...)
 {
 	char buffer[1024];
-	va_list ap;
+	std::va_list ap;
 	va_start(ap, fmt);
 	vsnprintf(buffer, sizeof(buffer), fmt, ap);
 	va_end(ap);
diff --git a/src/util/FormatString.cxx b/src/util/FormatString.cxx
index c26702e75..3ae0986b1 100644
--- a/src/util/FormatString.cxx
+++ b/src/util/FormatString.cxx
@@ -24,9 +24,9 @@
 #include <stdlib.h>
 
 AllocatedString<>
-FormatStringV(const char *fmt, va_list args) noexcept
+FormatStringV(const char *fmt, std::va_list args) noexcept
 {
-	va_list tmp;
+	std::va_list tmp;
 	va_copy(tmp, args);
 	const int length = vsnprintf(nullptr, 0, fmt, tmp);
 	va_end(tmp);
@@ -43,7 +43,7 @@ FormatStringV(const char *fmt, va_list args) noexcept
 AllocatedString<>
 FormatString(const char *fmt, ...) noexcept
 {
-	va_list args;
+	std::va_list args;
 	va_start(args, fmt);
 	auto p = FormatStringV(fmt, args);
 	va_end(args);
diff --git a/src/util/FormatString.hxx b/src/util/FormatString.hxx
index cec827537..e1ecc8500 100644
--- a/src/util/FormatString.hxx
+++ b/src/util/FormatString.hxx
@@ -22,7 +22,7 @@
 
 #include "Compiler.h"
 
-#include <stdarg.h>
+#include <cstdarg>
 
 template<typename T> class AllocatedString;
 
@@ -32,7 +32,7 @@ template<typename T> class AllocatedString;
  */
 gcc_nonnull_all
 AllocatedString<char>
-FormatStringV(const char *fmt, va_list args) noexcept;
+FormatStringV(const char *fmt, std::va_list args) noexcept;
 
 /**
  * Format into a newly allocated string.  The caller frees the return