From 3992712ad624a79ff569abba940a68f568140d80 Mon Sep 17 00:00:00 2001
From: Shuanglei Tao <tsl0922@gmail.com>
Date: Fri, 10 Jan 2025 15:24:56 +0800
Subject: [PATCH] Fix Print::printf implementation

---
 cores/nRF5/Print.cpp | 18 ++++++++++++------
 cores/nRF5/Print.h   |  2 +-
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/cores/nRF5/Print.cpp b/cores/nRF5/Print.cpp
index 2cce751..e3df795 100644
--- a/cores/nRF5/Print.cpp
+++ b/cores/nRF5/Print.cpp
@@ -187,13 +187,19 @@ size_t Print::println(const Printable& x)
   return n;
 }
 
-int Print::printf(const char* format, ...)
+size_t Print::printf(const char * format, ...)
 {
-  va_list va;
-  va_start(va, format);
-  int ret = vprintf(format, va);
-  va_end(va);
-  return ret;
+  char buf[256];
+  int len;
+
+  va_list ap;
+  va_start(ap, format);
+
+  len = vsnprintf(buf, 256, format, ap);
+  this->write(buf, len);
+
+  va_end(ap);
+  return len;
 }
 
 // Private Methods /////////////////////////////////////////////////////////////
diff --git a/cores/nRF5/Print.h b/cores/nRF5/Print.h
index 8b37c9f..15d23d2 100644
--- a/cores/nRF5/Print.h
+++ b/cores/nRF5/Print.h
@@ -83,7 +83,7 @@ class Print
     size_t println(double, int = 2);
     size_t println(const Printable&);
     size_t println(void);
-    int    printf(const char* format, ...) __attribute__ ((format (printf, 2, 3)));
+    size_t printf(const char* format, ...) __attribute__ ((format (printf, 2, 3)));
 
     virtual void flush() { /* Empty implementation for backward compatibility */ }