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// Copyright (c) 2010 Baidu.com, Inc. All Rights Reserved
//
// Add customized errno.
//
// Author: Ge,Jun (gejun@baidu.com)
// Date: Fri Sep 10 13:34:25 CST 2010
#ifndef BRPC_BASE_BAIDU_ERRNO_H
#define BRPC_BASE_BAIDU_ERRNO_H
#define __const__
#include <errno.h> // errno
#include "base/macros.h" // BAIDU_CONCAT
//-----------------------------------------
// Use system errno before defining yours !
//-----------------------------------------
//
// To add new errno, you shall define the errno in header first, either by
// macro or constant, or even in protobuf.
//
// #define ESTOP -114 // C/C++
// static const int EMYERROR = 30; // C/C++
// const int EMYERROR2 = -31; // C++ only
//
// Then you can register description of the error by calling
// BAIDU_REGISTER_ERRNO(the_error_number, its_description) in global scope of
// a .cpp or .cc files which will be linked.
//
// BAIDU_REGISTER_ERRNO(ESTOP, "the thread is stopping")
// BAIDU_REGISTER_ERRNO(EMYERROR, "my error")
//
// Once the error is successfully defined:
// berror(error_code) returns the description.
// berror() returns description of last system error code.
//
// %m in printf-alike functions does NOT recognize errors defined by
// BAIDU_REGISTER_ERRNO, you have to explicitly print them by %s.
//
// errno = ESTOP;
// printf("Something got wrong, %m\n"); // NO
// printf("Something got wrong, %s\n", berror()); // YES
//
// When the error number is re-defined, a linking error will be reported:
//
// "redefinition of `class BaiduErrnoHelper<30>'"
//
// Or the program aborts at runtime before entering main():
//
// "Fail to define EMYERROR(30) which is already defined as `Read-only file system', abort"
//
namespace base {
// You should not call this function, use BAIDU_REGISTER_ERRNO instead.
extern int DescribeCustomizedErrno(int, const char*, const char*);
}
template <int error_code> class BaiduErrnoHelper {};
#define BAIDU_REGISTER_ERRNO(error_code, description) \
const int ALLOW_UNUSED BAIDU_CONCAT(baidu_errno_dummy_, __LINE__) = \
::base::DescribeCustomizedErrno((error_code), #error_code, (description)); \
template <> class BaiduErrnoHelper<(int)(error_code)> {};
const char* berror(int error_code);
const char* berror();
#endif //BRPC_BASE_BAIDU_ERRNO_H