From: Martin Ling <redacted>
Date: Fri, 24 Jan 2020 04:30:22 +0000 (+0000)
Subject: windows: Use correct variant of FormatMessage.
X-Git-Tag: libserialport-0.1.2~42
X-Git-Url: https://sigrok.org/gitaction?a=commitdiff_plain;h=bf40b1cea9eb2e13d13f05118fe11b43be621485;p=libserialport.git

windows: Use correct variant of FormatMessage.

When built with MSVC and unicode enabled, using 'message' gave:

warning C4133: 'initializing': incompatible types - from 'TCHAR *' to 'char *'

FormatMessage expands to either FormatMessageA or FormatMessageW
depending if unicode is enabled, and generates either a char (8-bit)
or WCHAR (UTF-16) string accordingly.

Since sp_last_error_message() returns char *, we must use the 8-bit
variant. The message will be encoded in the current code page.
---

diff --git a/serialport.c b/serialport.c
index 0a46688..eee453a 100644
--- a/serialport.c
+++ b/serialport.c
@@ -2478,17 +2478,17 @@ SP_API char *sp_last_error_message(void)
 	TRACE_VOID();
 
 #ifdef _WIN32
-	TCHAR *message;
+	char *message;
 	DWORD error = GetLastError();
 
-	DWORD length = FormatMessage(
+	DWORD length = FormatMessageA(
 		FORMAT_MESSAGE_ALLOCATE_BUFFER |
 		FORMAT_MESSAGE_FROM_SYSTEM |
 		FORMAT_MESSAGE_IGNORE_INSERTS,
 		NULL,
 		error,
 		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-		(LPTSTR) &message,
+		(LPSTR) &message,
 		0, NULL );
 
 	if (length >= 2 && message[length - 2] == '\r')