error_checking/system.cpp at master · godefv/error_checking · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
#include"system.h"

#ifdef _WIN32
	#include<windows.h>
#else
	#include<cerrno>
	#include<cstring>
#endif

namespace godefv{namespace os{

error_t::error_t(int errcode):code(errcode){}

#ifdef _WIN32
std::string error_t::string() const{
	if(!code) return std::string{"(no error)"};

	LPVOID lpMsgBuf;
	DWORD bufLen = FormatMessage(
			FORMAT_MESSAGE_ALLOCATE_BUFFER |
			FORMAT_MESSAGE_FROM_SYSTEM |
			FORMAT_MESSAGE_IGNORE_INSERTS,
			NULL,
			code,
			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
			(LPTSTR) &lpMsgBuf,
			0, NULL );
	if(!bufLen) return std::string{};

	LPCSTR lpMsgStr = (LPCSTR)lpMsgBuf;
	std::string result(lpMsgStr, lpMsgStr+bufLen);

	LocalFree(lpMsgBuf);

	return result;
}
#else
std::string error_t::string() const{
	char * e = strerror(code);
	return e ? e : "";
}
#endif

error_t last_error() noexcept{
#ifdef _WIN32
	return error_t{static_cast<int>(GetLastError())};
#else
	return error_t{errno};
#endif
}

}} /* namespace godefv::os */