syscall: more changes to mingw version

- mkall now generates syscall stabs automatically
- we can call unicode versions of winapi now
- introduce GetErrstr function to fetch error text given errno
- general cleanup

R=rsc
CC=golang-dev
https://golang.org/cl/562041

src/pkg/runtime/mingw/syscall.cgo

@@ -6,6 +6,18 @@ package syscall
 #include "runtime.h"
 #include "os.h"
 
+static uintptr
+stdcallerr(uintptr *lasterr, uintptr trap, uintptr a1, uintptr a2, uintptr a3, uintptr a4, uintptr a5, uintptr a6, uintptr a7, uintptr a8, uintptr a9)
+{
+	uintptr r;
+
+	·entersyscall();
+	r = (uintptr)stdcall_raw((void*)trap, a1, a2, a3, a4, a5, a6, a7, a8, a9);
+	*lasterr = (uintptr)stdcall_raw(GetLastError);
+	·exitsyscall();
+	return r;
+}
+
 func loadlibraryex(filename uintptr) (handle uint32) {
 	handle = (uint32)stdcall(LoadLibraryEx, filename, 0, 0);
 }
@@ -15,19 +27,18 @@ func getprocaddress(handle uint32, procname uintptr) (proc uintptr) {
 }
 
 func Syscall(trap uintptr, a1 uintptr, a2 uintptr, a3 uintptr) (r1 uintptr, r2 uintptr, err uintptr) {
-	·entersyscall();
-	r1 = (uintptr)stdcall_raw((void*)trap, a1, a2, a3);
+	r1 = stdcallerr(&err, trap, a1, a2, a3, 0, 0, 0, 0, 0, 0);
 	r2 = 0;
-	err = (uintptr)stdcall_raw(GetLastError);
-	·exitsyscall();
 }
 
 func Syscall6(trap uintptr, a1 uintptr, a2 uintptr, a3 uintptr, a4 uintptr, a5 uintptr, a6 uintptr) (r1 uintptr, r2 uintptr, err uintptr) {
-	·entersyscall();
-	r1 = (uintptr)stdcall_raw((void*)trap, a1, a2, a3, a4, a5, a6);
+	r1 = stdcallerr(&err, trap, a1, a2, a3, a4, a5, a6, 0, 0, 0);
+	r2 = 0;
+}
+
+func Syscall9(trap uintptr, a1 uintptr, a2 uintptr, a3 uintptr, a4 uintptr, a5 uintptr, a6 uintptr, a7 uintptr, a8 uintptr, a9 uintptr) (r1 uintptr, r2 uintptr, lasterr uintptr) {
+	r1 = stdcallerr(&lasterr, trap, a1, a2, a3, a4, a5, a6, a7, a8, a9);
 	r2 = 0;
-	err = (uintptr)stdcall_raw(GetLastError);
-	·exitsyscall();
 }
 
 func RawSyscall(trap uintptr, a1 uintptr, a2 uintptr, a3 uintptr) (r1 uintptr, r2 uintptr, err uintptr) {

src/pkg/syscall/mkall.sh

@@ -145,11 +145,10 @@ linux_arm)
 	mkerrors="mkerrors.sh"
 	;;
 mingw_386)
-	# TODO(brainman): create proper mksyscall / mksysnum / mktypes
-	mksyscall="mksyscall.sh -l32"
-	mksysnum="XXXXXX_mksysnum.sh"
-	mktypes="XXXXXX_godefs -gsyscall -f-m32"
-	exit 1
+	mksyscall="mksyscall_mingw.sh -l32"
+	mksysnum=
+	mktypes=
+	mkerrors=
 	;;
 *)
 	echo 'unrecognized $GOOS_$GOARCH: ' "$GOOSARCH" 1>&2
@@ -158,8 +157,8 @@ mingw_386)
 esac
 
 (
-	echo "$mkerrors |gofmt >zerrors_$GOOSARCH.go"
-	echo "$mksyscall syscall_$GOOS.go syscall_$GOOSARCH.go |gofmt >zsyscall_$GOOSARCH.go"
-	echo "$mksysnum |gofmt >zsysnum_$GOOSARCH.go"
-	echo "$mktypes types_$GOOS.c |gofmt >ztypes_$GOOSARCH.go"
+	if [ -n "$mkerrors" ]; then echo "$mkerrors |gofmt >zerrors_$GOOSARCH.go"; fi
+	if [ -n "$mksyscall" ]; then echo "$mksyscall syscall_$GOOS.go syscall_$GOOSARCH.go |gofmt >zsyscall_$GOOSARCH.go"; fi
+	if [ -n "$mksysnum" ]; then echo "$mksysnum |gofmt >zsysnum_$GOOSARCH.go"; fi
+	if [ -n "$mktypes" ]; then echo "$mktypes types_$GOOS.c |gofmt >ztypes_$GOOSARCH.go"; fi
 ) | $run

src/pkg/syscall/mksyscall_mingw.sh

+#!/usr/bin/perl
+# Copyright 2009 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+# This program reads a file containing function prototypes
+# (like syscall_darwin.go) and generates system call bodies.
+# The prototypes are marked by lines beginning with "//sys"
+# and read like func declarations if //sys is replaced by func, but:
+#	* The parameter lists must give a name for each argument.
+#	  This includes return parameters.
+#	* The parameter lists must give a type for each argument:
+#	  the (x, y, z int) shorthand is not allowed.
+#	* If the return parameter is an error number, it must be named errno.
+#	* If go func name needs to be different from it's winapi dll name,
+#	  the winapi name could be specified at the end, after "=" sign, like
+#	  //sys LoadLibrary(libname string) (handle uint32, errno int) = LoadLibraryA
+#	* Each function, that returns errno, needs to supply a number,
+#	  that return value of winapi will be tested against to
+#	  detect failure. This would set errno to windows "last-error",
+#	  otherwise it will be 0. The value can be provided at
+#	  the very end of //sys declaration, like
+#	  //sys LoadLibrary(libname string) (handle uint32, errno int) = LoadLibraryA, 0xffffffff
+#	  and is 0 by default.
+
+$cmdline = "mksyscall_mingw.sh " . join(' ', @ARGV);
+$errors = 0;
+$_32bit = "";
+
+if($ARGV[0] eq "-b32") {
+	$_32bit = "big-endian";
+	shift;
+} elsif($ARGV[0] eq "-l32") {
+	$_32bit = "little-endian";
+	shift;
+}
+
+if($ARGV[0] =~ /^-/) {
+	print STDERR "usage: mksyscall_mingw.sh [-b32 | -l32] [file ...]\n";
+	exit 1;
+}
+
+sub parseparamlist($) {
+	my ($list) = @_;
+	$list =~ s/^\s*//;
+	$list =~ s/\s*$//;
+	if($list eq "") {
+		return ();
+	}
+	return split(/\s*,\s*/, $list);
+}
+
+sub parseparam($) {
+	my ($p) = @_;
+	if($p !~ /^(\S*) (\S*)$/) {
+		print STDERR "$ARGV:$.: malformed parameter: $p\n";
+		$errors = 1;
+		return ("xx", "int");
+	}
+	return ($1, $2);
+}
+
+$text = "";
+$vars = "";
+while(<>) {
+	chomp;
+	s/\s+/ /g;
+	s/^\s+//;
+	s/\s+$//;
+	next if !/^\/\/sys /;
+
+	# Line must be of the form
+	#	func Open(path string, mode int, perm int) (fd int, errno int)
+	# Split into name, in params, out params.
+	if(!/^\/\/sys (\w+)\(([^()]*)\)\s*(?:\(([^()]+)\))?\s*(?:=\s*(\w*))?(?:\s*,\s*(\w+))?$/) {
+		print STDERR "$ARGV:$.: malformed //sys declaration\n";
+		$errors = 1;
+		next;
+	}
+	my ($func, $in, $out, $sysname, $failretval) = ($1, $2, $3, $4, $5);
+
+	# Split argument lists on comma.
+	my @in = parseparamlist($in);
+	my @out = parseparamlist($out);
+
+	# System call name.
+	if($sysname eq "") {
+		$sysname = "$func";
+	}
+
+	# System call pointer variable name.
+	$sysvarname = "proc$sysname";
+
+	# Returned value when failed
+	if($failretval eq "") {
+		$failretval = "0";
+	}
+
+	# Decide which version of api is used: ascii or unicode.
+	if($sysname !~ /W$/) {
+		$strconvfunc = "StringBytePtr";
+	} else {
+		$strconvfunc = "StringToUTF16Ptr";
+	}
+
+	# Winapi proc address variable.
+	$vars .= sprintf "\t%s = getSysProcAddr(modKERNEL32, \"%s\")\n", $sysvarname, $sysname;
+
+	# Go function header.
+	$text .= sprintf "func %s(%s) (%s) {\n", $func, join(', ', @in), join(', ', @out);
+
+	# Prepare arguments to Syscall9.
+	my @args = ();
+	my $n = 0;
+	foreach my $p (@in) {
+		my ($name, $type) = parseparam($p);
+		if($type =~ /^\*/) {
+			push @args, "uintptr(unsafe.Pointer($name))";
+		} elsif($type eq "string") {
+			push @args, "uintptr(unsafe.Pointer($strconvfunc($name)))";
+		} elsif($type =~ /^\[\](.*)/) {
+			# Convert slice into pointer, length.
+			# Have to be careful not to take address of &a[0] if len == 0:
+			# pass nil in that case.
+			$text .= "\tvar _p$n *$1;\n";
+			$text .= "\tif len($name) > 0 { _p$n = \&${name}[0]; }\n";
+			push @args, "uintptr(unsafe.Pointer(_p$n))", "uintptr(len($name))";
+			$n++;
+		} elsif($type eq "int64" && $_32bit ne "") {
+			if($_32bit eq "big-endian") {
+				push @args, "uintptr($name >> 32)", "uintptr($name)";
+			} else {
+				push @args, "uintptr($name)", "uintptr($name >> 32)";
+			}
+		} else {
+			push @args, "uintptr($name)";
+		}
+	}
+
+	# Determine which form to use; pad args with zeros.
+	my $asm = "Syscall9";
+	if(@args <= 9) {
+		while(@args < 9) {
+			push @args, "0";
+		}
+	} else {
+		print STDERR "$ARGV:$.: too many arguments to system call\n";
+	}
+
+	# Actual call.
+	my $args = join(', ', @args);
+	my $call = "$asm($sysvarname, $args)";
+
+	# Assign return values.
+	my $body = "";
+	my @ret = ("_", "_", "_");
+	for(my $i=0; $i<@out; $i++) {
+		my $p = $out[$i];
+		my ($name, $type) = parseparam($p);
+		my $reg = "";
+		if($name eq "errno") {
+			$reg = "e1";
+			$ret[2] = $reg;
+		} else {
+			$reg = sprintf("r%d", $i);
+			$ret[$i] = $reg;
+		}
+		if($type eq "bool") {
+			$reg = "$reg != 0";
+		}
+		if($type eq "int64" && $_32bit ne "") {
+			# 64-bit number in r1:r0 or r0:r1.
+			if($i+2 > @out) {
+				print STDERR "$ARGV:$.: not enough registers for int64 return\n";
+			}
+			if($_32bit eq "big-endian") {
+				$reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i, $i+1);
+			} else {
+				$reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i+1, $i);
+			}
+			$ret[$i] = sprintf("r%d", $i);
+			$ret[$i+1] = sprintf("r%d", $i+1);
+		}
+		if($name eq "errno") {
+			# Set errno to "last error" only if returned value indicate failure
+			$body .= "\tif uint32(r0) == $failretval {\n";
+			$body .= "\t\t$name = $type($reg);\n";
+			$body .= "\t} else {\n";
+			$body .= "\t\t$name = 0;\n";
+			$body .= "\t}\n";
+		} else {
+			$body .= "\t$name = $type($reg);\n";
+		}
+	}
+	if ($ret[0] eq "_" && $ret[1] eq "_" && $ret[2] eq "_") {
+		$text .= "\t$call;\n";
+	} else {
+		$text .= "\t$ret[0], $ret[1], $ret[2] := $call;\n";
+	}
+	$text .= $body;
+
+	$text .= "\treturn;\n";
+	$text .= "}\n\n";
+}
+
+if($errors) {
+	exit 1;
+}
+
+print <<EOF;
+// $cmdline
+// MACHINE GENERATED BY THE COMMAND ABOVE; DO NOT EDIT
+
+package syscall
+
+import "unsafe"
+
+var (
+	modKERNEL32 = loadDll("kernel32.dll")
+$vars
+)
+
+$text
+
+EOF
+exit 0;

src/pkg/syscall/syscall_mingw.go

@@ -6,7 +6,10 @@
 
 package syscall
 
-import "unsafe"
+import (
+	"unsafe"
+	"utf16"
+)
 
 const OS = "mingw"
 
@@ -20,6 +23,10 @@ import (
 	"syscall"
 )
 
+func abort(funcname string, err int) {
+	panic(funcname+" failed: (", err, ") ", syscall.GetErrstr(err), "\n")
+}
+
 func print_version(v uint32) {
 	major := byte(v)
 	minor := uint8(v >> 8)
@@ -30,69 +37,90 @@ func print_version(v uint32) {
 func main() {
 	h, err := syscall.LoadLibrary("kernel32.dll")
 	if err != 0 {
-		panic("failed to LoadLibrary #", err, "\n")
+		abort("LoadLibrary", err)
 	}
 	defer syscall.FreeLibrary(h)
 	proc, err := syscall.GetProcAddress(h, "GetVersion")
 	if err != 0 {
-		panic("could not GetProcAddress #", err, "\n")
-	}
-	r, _, e := syscall.Syscall(uintptr(proc), 0, 0, 0)
-	err = int(e)
-	if err != 0 {
-		panic("GetVersion failed #", err, "\n")
+		abort("GetProcAddress", err)
 	}
+	r, _, _ := syscall.Syscall(uintptr(proc), 0, 0, 0)
 	print_version(uint32(r))
 }
 
 */
 
-//sys	GetLastError() (lasterrno int)
-
-// TODO(brainman): probably should use LoadLibraryW here instead
-//sys	LoadLibraryA(libname string) (handle Module, errno int)
+// StringToUTF16 returns the UTF-16 encoding of the UTF-8 string s,
+// with a terminating NUL added.
+func StringToUTF16(s string) []uint16 { return utf16.Encode([]int(s + "\x00")) }
 
-func LoadLibrary(libname string) (handle Module, errno int) {
-	h, e := LoadLibraryA(libname)
-	if int(h) != 0 {
-		return h, 0
+// UTF16ToString returns the UTF-8 encoding of the UTF-16 sequence s,
+// with a terminating NUL removed.
+func UTF16ToString(s []uint16) string {
+	if n := len(s); n > 0 && s[n-1] == 0 {
+		s = s[0 : n-1]
 	}
-	return h, e
+	return string(utf16.Decode(s))
 }
 
-// TODO(brainman): should handle errors like in LoadLibrary, otherwise will be returning 'old' errors
-//sys	FreeLibrary(handle Module) (ok Bool, errno int)
-//sys	GetProcAddress(module Module, procname string) (proc uint32, errno int)
-//sys	GetVersion() (ver uint32, errno int)
+// StringToUTF16Ptr returns pointer to the UTF-16 encoding of
+// the UTF-8 string s, with a terminating NUL added.
+func StringToUTF16Ptr(s string) *uint16 { return &StringToUTF16(s)[0] }
 
 // dll helpers
 
 // implemented in ../pkg/runtime/mingw/syscall.cgo
+func Syscall9(trap, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2, lasterr uintptr)
 func loadlibraryex(filename uintptr) (handle uint32)
 func getprocaddress(handle uint32, procname uintptr) (proc uintptr)
 
-func loadDll(fname string) Module {
+func loadDll(fname string) uint32 {
 	m := loadlibraryex(uintptr(unsafe.Pointer(StringBytePtr(fname))))
 	if m == 0 {
 		panic("syscall: could not LoadLibraryEx ", fname)
 	}
-	return Module(m)
+	return m
 }
 
-func getSysProcAddr(m Module, pname string) uintptr {
-	p := getprocaddress(uint32(m), uintptr(unsafe.Pointer(StringBytePtr(pname))))
+func getSysProcAddr(m uint32, pname string) uintptr {
+	p := getprocaddress(m, uintptr(unsafe.Pointer(StringBytePtr(pname))))
 	if p == 0 {
 		panic("syscall: could not GetProcAddress for ", pname)
 	}
 	return p
 }
 
+// windows api calls
+
+//sys	GetLastError() (lasterrno int)
+//sys	LoadLibrary(libname string) (handle uint32, errno int) = LoadLibraryW
+//sys	FreeLibrary(handle uint32) (ok bool, errno int)
+//sys	GetProcAddress(module uint32, procname string) (proc uint32, errno int)
+//sys	GetVersion() (ver uint32, errno int)
+//sys	FormatMessage(flags uint32, msgsrc uint32, msgid uint32, langid uint32, buf []uint16, args *byte) (n uint32, errno int) = FormatMessageW
+
+// TODO(brainman): maybe GetErrstr should replace Errstr alltogether
+
+func GetErrstr(errno int) string {
+	if errno == EMINGW {
+		return errors[errno]
+	}
+	var b = make([]uint16, 300)
+	n, err := FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_ARGUMENT_ARRAY, 0, uint32(errno), 0, b, nil)
+	if err != 0 {
+		return "error " + str(errno) + " (FormatMessage failed with err=" + str(err) + ")"
+	}
+	return UTF16ToString(b[0 : n-1])
+}
+
 // TODO(brainman): fix all this meaningless code, it is here to compile exec.go
 
 func Pipe(p []int) (errno int) { return EMINGW }
 
-//sys	Close(fd int) (errno int)
-//sys	read(fd int, buf *byte, nbuf int) (n int, errno int)
+func Close(fd int) (errno int) { return EMINGW }
+func read(fd int, buf *byte, nbuf int) (n int, errno int) {
+	return 0, EMINGW
+}
 
 func fcntl(fd, cmd, arg int) (val int, errno int) {
 	return 0, EMINGW

src/pkg/syscall/zerrors_mingw_386.go

@@ -6,7 +6,11 @@ package syscall
 // TODO(brainman): populate errors in zerrors_mingw.go
 
 const (
-	EMINGW = 99 /* otherwise unused */
+	ERROR_INSUFFICIENT_BUFFER = 122
+	ERROR_MOD_NOT_FOUND       = 126
+	ERROR_PROC_NOT_FOUND      = 127
+	// TODO(brainman): should use value for EMINGW that does not clashes with anything else
+	EMINGW = 99999 /* otherwise unused */
 )
 
 // Error table

src/pkg/syscall/zsyscall_mingw_386.go

-// mksyscall.sh -l32 syscall_mingw.go
+// mksyscall_mingw.sh -l32 syscall_mingw.go syscall_mingw_386.go
 // MACHINE GENERATED BY THE COMMAND ABOVE; DO NOT EDIT
 
 package syscall
 
 import "unsafe"
 
+var (
+	modKERNEL32        = loadDll("kernel32.dll")
+	procGetLastError   = getSysProcAddr(modKERNEL32, "GetLastError")
+	procLoadLibraryW   = getSysProcAddr(modKERNEL32, "LoadLibraryW")
+	procFreeLibrary    = getSysProcAddr(modKERNEL32, "FreeLibrary")
+	procGetProcAddress = getSysProcAddr(modKERNEL32, "GetProcAddress")
+	procGetVersion     = getSysProcAddr(modKERNEL32, "GetVersion")
+	procFormatMessageW = getSysProcAddr(modKERNEL32, "FormatMessageW")
+)
+
 func GetLastError() (lasterrno int) {
-	r0, _, _ := Syscall(SYS_GET_LAST_ERROR, 0, 0, 0)
+	r0, _, _ := Syscall9(procGetLastError, 0, 0, 0, 0, 0, 0, 0, 0, 0)
 	lasterrno = int(r0)
 	return
 }
 
-func LoadLibraryA(libname string) (handle Module, errno int) {
-	r0, _, e1 := Syscall(SYS_LOAD_LIBRARY_A, uintptr(unsafe.Pointer(StringBytePtr(libname))), 0, 0)
-	handle = Module(r0)
+func LoadLibrary(libname string) (handle uint32, errno int) {
+	r0, _, e1 := Syscall9(procLoadLibraryW, uintptr(unsafe.Pointer(StringToUTF16Ptr(libname))), 0, 0, 0, 0, 0, 0, 0, 0)
+	handle = uint32(r0)
+	if uint32(r0) == 0 {
 		errno = int(e1)
+	} else {
+		errno = 0
+	}
 	return
 }
 
-func FreeLibrary(handle Module) (ok Bool, errno int) {
-	r0, _, e1 := Syscall(SYS_FREE_LIBRARY, uintptr(handle), 0, 0)
-	ok = Bool(r0)
+func FreeLibrary(handle uint32) (ok bool, errno int) {
+	r0, _, e1 := Syscall9(procFreeLibrary, uintptr(handle), 0, 0, 0, 0, 0, 0, 0, 0)
+	ok = bool(r0 != 0)
+	if uint32(r0) == 0 {
 		errno = int(e1)
+	} else {
+		errno = 0
+	}
 	return
 }
 
-func GetProcAddress(module Module, procname string) (proc uint32, errno int) {
-	r0, _, e1 := Syscall(SYS_GET_PROC_ADDRESS, uintptr(module), uintptr(unsafe.Pointer(StringBytePtr(procname))), 0)
+func GetProcAddress(module uint32, procname string) (proc uint32, errno int) {
+	r0, _, e1 := Syscall9(procGetProcAddress, uintptr(module), uintptr(unsafe.Pointer(StringBytePtr(procname))), 0, 0, 0, 0, 0, 0, 0)
 	proc = uint32(r0)
+	if uint32(r0) == 0 {
 		errno = int(e1)
+	} else {
+		errno = 0
+	}
 	return
 }
 
 func GetVersion() (ver uint32, errno int) {
-	r0, _, e1 := Syscall(SYS_GET_VERSION, 0, 0, 0)
+	r0, _, e1 := Syscall9(procGetVersion, 0, 0, 0, 0, 0, 0, 0, 0, 0)
 	ver = uint32(r0)
+	if uint32(r0) == 0 {
 		errno = int(e1)
+	} else {
+		errno = 0
+	}
 	return
 }
 
-func Close(fd int) (errno int) {
-	_, _, e1 := Syscall(SYS_CLOSE, uintptr(fd), 0, 0)
-	errno = int(e1)
-	return
-}
-
-func read(fd int, buf *byte, nbuf int) (n int, errno int) {
-	r0, _, e1 := Syscall(SYS_READ, uintptr(fd), uintptr(unsafe.Pointer(buf)), uintptr(nbuf))
-	n = int(r0)
+func FormatMessage(flags uint32, msgsrc uint32, msgid uint32, langid uint32, buf []uint16, args *byte) (n uint32, errno int) {
+	var _p0 *uint16
+	if len(buf) > 0 {
+		_p0 = &buf[0]
+	}
+	r0, _, e1 := Syscall9(procFormatMessageW, uintptr(flags), uintptr(msgsrc), uintptr(msgid), uintptr(langid), uintptr(unsafe.Pointer(_p0)), uintptr(len(buf)), uintptr(unsafe.Pointer(args)), 0, 0)
+	n = uint32(r0)
+	if uint32(r0) == 0 {
 		errno = int(e1)
+	} else {
+		errno = 0
+	}
 	return
 }

src/pkg/syscall/zsysnum_mingw_386.go

@@ -2,14 +2,3 @@
 // MACHINE GENERATED BY THE ABOVE COMMAND; DO NOT EDIT
 
 package syscall
-
-// TODO(brainman): autogenerate winapi proc pointers in zsysnum_mingw.go
-
-var (
-	SYS_KERNEL32         = loadDll("kernel32.dll")
-	SYS_GET_LAST_ERROR   = getSysProcAddr(SYS_KERNEL32, "GetLastError")
-	SYS_LOAD_LIBRARY_A   = getSysProcAddr(SYS_KERNEL32, "LoadLibraryA")
-	SYS_FREE_LIBRARY     = getSysProcAddr(SYS_KERNEL32, "FreeLibrary")
-	SYS_GET_PROC_ADDRESS = getSysProcAddr(SYS_KERNEL32, "GetProcAddress")
-	SYS_GET_VERSION      = getSysProcAddr(SYS_KERNEL32, "GetVersion")
-)

src/pkg/syscall/ztypes_mingw_386.go

@@ -25,6 +25,16 @@ const (
 	SizeofCmsghdr       = 0xc
 )
 
+const (
+	FORMAT_MESSAGE_ALLOCATE_BUFFER = 256
+	FORMAT_MESSAGE_IGNORE_INSERTS  = 512
+	FORMAT_MESSAGE_FROM_STRING     = 1024
+	FORMAT_MESSAGE_FROM_HMODULE    = 2048
+	FORMAT_MESSAGE_FROM_SYSTEM     = 4096
+	FORMAT_MESSAGE_ARGUMENT_ARRAY  = 8192
+	FORMAT_MESSAGE_MAX_WIDTH_MASK  = 255
+)
+
 // Types
 
 type _C_short int16
@@ -35,9 +45,6 @@ type _C_long int32
 
 type _C_long_long int64
 
-type Bool uint32
-type Module uint32
-
 type Timeval struct {
 	Sec  int32
 	Usec int32