windows: Use correct variant of CreateFile.

When built with MSVC and unicode enabled, using CreateFile gave:

warning C4133: 'function': incompatible types - from 'char *' to 'LPCWSTR'

CreateFile is a macro expanding to either CreateFileW if unicode
mode is enabled, or CreateFileA if not.

For CreateFileW, the filename is a UTF-16 string. For CreateFileA
it is an 'ANSI' string, meaning 8-bit chars in the current Windows
code page.

We do need to stick to 8-bit strings for port names, since
sp_get_port_by_name() and sp_get_port_name() are defined with
char * types, and that is what we store in struct sp_port. So
CreateFileA is the correct version to use.

Since Windows serial port names are always just 'COM' and a digit,
with a '\\.\' prefix for higher numbers, encoding is fortunately
not an issue - ASCII, UTF-8 and all the Windows code pages seem to
be equivalent for these characters.

We should however explicitly document what the encoding of strings
accepted and returned by libserialport is.

diff --git a/serialport.c b/serialport.c
index b2e4a7984fdcf2738209bc74cacd60f66c693a9b..0a466887da1eddcbe72f642e007c0fb90417bdf1 100644 (file)
--- a/serialport.c
+++ b/serialport.c
@@ -488,7 +488,7 @@ SP_API enum sp_return sp_open(struct sp_port *port, enum sp_mode flags)
        if (flags & SP_MODE_WRITE)
                desired_access |= GENERIC_WRITE;
 
-       port->hdl = CreateFile(escaped_port_name, desired_access, 0, 0,
+       port->hdl = CreateFileA(escaped_port_name, desired_access, 0, 0,
                         OPEN_EXISTING, flags_and_attributes, 0);
 
        free(escaped_port_name);

diff --git a/windows.c b/windows.c
index 0521716549272d558418e3f826cf10870c271672..bc07e234c341ebf8cdec4d34aa1344ae2fe4429a 100644 (file)
--- a/windows.c
+++ b/windows.c
@@ -467,9 +467,9 @@ SP_PRIV enum sp_return get_port_details(struct sp_port *port)
                        if (!(escaped_port_name = malloc(strlen(port->name) + 5)))
                                RETURN_ERROR(SP_ERR_MEM, "Escaped port name malloc failed");
                        sprintf(escaped_port_name, "\\\\.\\%s", port->name);
-                       handle = CreateFile(escaped_port_name, GENERIC_READ, 0, 0,
-                                           OPEN_EXISTING,
-                                           FILE_ATTRIBUTE_NORMAL|FILE_FLAG_OVERLAPPED, 0);
+                       handle = CreateFileA(escaped_port_name, GENERIC_READ, 0, 0,
+                                            OPEN_EXISTING,
+                                            FILE_ATTRIBUTE_NORMAL|FILE_FLAG_OVERLAPPED, 0);
                        free(escaped_port_name);
                        CloseHandle(handle);