add googleglog

x86_64-ubuntu1604/include/googleglog/log_severity.h

+// Copyright (c) 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef BASE_LOG_SEVERITY_H__
+#define BASE_LOG_SEVERITY_H__
+
+// Annoying stuff for windows -- makes sure clients can import these functions
+#ifndef GOOGLE_GLOG_DLL_DECL
+# if defined(_WIN32) && !defined(__CYGWIN__)
+#   define GOOGLE_GLOG_DLL_DECL  __declspec(dllimport)
+# else
+#   define GOOGLE_GLOG_DLL_DECL
+# endif
+#endif
+
+// Variables of type LogSeverity are widely taken to lie in the range
+// [0, NUM_SEVERITIES-1].  Be careful to preserve this assumption if
+// you ever need to change their values or add a new severity.
+typedef int LogSeverity;
+
+const int GLOG_INFO = 0, GLOG_WARNING = 1, GLOG_ERROR = 2, GLOG_FATAL = 3,
+  NUM_SEVERITIES = 4;
+#ifndef GLOG_NO_ABBREVIATED_SEVERITIES
+# ifdef ERROR
+#  error ERROR macro is defined. Define GLOG_NO_ABBREVIATED_SEVERITIES before including logging.h. See the document for detail.
+# endif
+const int INFO = GLOG_INFO, WARNING = GLOG_WARNING,
+  ERROR = GLOG_ERROR, FATAL = GLOG_FATAL;
+#endif
+
+// DFATAL is FATAL in debug mode, ERROR in normal mode
+#ifdef NDEBUG
+#define DFATAL_LEVEL ERROR
+#else
+#define DFATAL_LEVEL FATAL
+#endif
+
+extern GOOGLE_GLOG_DLL_DECL const char* const LogSeverityNames[NUM_SEVERITIES];
+
+// NDEBUG usage helpers related to (RAW_)DCHECK:
+//
+// DEBUG_MODE is for small !NDEBUG uses like
+//   if (DEBUG_MODE) foo.CheckThatFoo();
+// instead of substantially more verbose
+//   #ifndef NDEBUG
+//     foo.CheckThatFoo();
+//   #endif
+//
+// IF_DEBUG_MODE is for small !NDEBUG uses like
+//   IF_DEBUG_MODE( string error; )
+//   DCHECK(Foo(&error)) << error;
+// instead of substantially more verbose
+//   #ifndef NDEBUG
+//     string error;
+//     DCHECK(Foo(&error)) << error;
+//   #endif
+//
+#ifdef NDEBUG
+enum { DEBUG_MODE = 0 };
+#define IF_DEBUG_MODE(x)
+#else
+enum { DEBUG_MODE = 1 };
+#define IF_DEBUG_MODE(x) x
+#endif
+
+#endif  // BASE_LOG_SEVERITY_H__

x86_64-ubuntu1604/include/googleglog/raw_logging.h

+// Copyright (c) 2006, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: Maxim Lifantsev
+//
+// Thread-safe logging routines that do not allocate any memory or
+// acquire any locks, and can therefore be used by low-level memory
+// allocation and synchronization code.
+
+#ifndef BASE_RAW_LOGGING_H_
+#define BASE_RAW_LOGGING_H_
+
+#include <time.h>
+
+namespace google {
+
+#include "glog/log_severity.h"
+#include "glog/vlog_is_on.h"
+
+// Annoying stuff for windows -- makes sure clients can import these functions
+#ifndef GOOGLE_GLOG_DLL_DECL
+# if defined(_WIN32) && !defined(__CYGWIN__)
+#   define GOOGLE_GLOG_DLL_DECL  __declspec(dllimport)
+# else
+#   define GOOGLE_GLOG_DLL_DECL
+# endif
+#endif
+
+// This is similar to LOG(severity) << format... and VLOG(level) << format..,
+// but
+// * it is to be used ONLY by low-level modules that can't use normal LOG()
+// * it is desiged to be a low-level logger that does not allocate any
+//   memory and does not need any locks, hence:
+// * it logs straight and ONLY to STDERR w/o buffering
+// * it uses an explicit format and arguments list
+// * it will silently chop off really long message strings
+// Usage example:
+//   RAW_LOG(ERROR, "Failed foo with %i: %s", status, error);
+//   RAW_VLOG(3, "status is %i", status);
+// These will print an almost standard log lines like this to stderr only:
+//   E0821 211317 file.cc:123] RAW: Failed foo with 22: bad_file
+//   I0821 211317 file.cc:142] RAW: status is 20
+#define RAW_LOG(severity, ...) \
+  do { \
+    switch (google::GLOG_ ## severity) {  \
+      case 0: \
+        RAW_LOG_INFO(__VA_ARGS__); \
+        break; \
+      case 1: \
+        RAW_LOG_WARNING(__VA_ARGS__); \
+        break; \
+      case 2: \
+        RAW_LOG_ERROR(__VA_ARGS__); \
+        break; \
+      case 3: \
+        RAW_LOG_FATAL(__VA_ARGS__); \
+        break; \
+      default: \
+        break; \
+    } \
+  } while (0)
+
+// The following STRIP_LOG testing is performed in the header file so that it's
+// possible to completely compile out the logging code and the log messages.
+#if STRIP_LOG == 0
+#define RAW_VLOG(verboselevel, ...) \
+  do { \
+    if (VLOG_IS_ON(verboselevel)) { \
+      RAW_LOG_INFO(__VA_ARGS__); \
+    } \
+  } while (0)
+#else
+#define RAW_VLOG(verboselevel, ...) RawLogStub__(0, __VA_ARGS__)
+#endif // STRIP_LOG == 0
+
+#if STRIP_LOG == 0
+#define RAW_LOG_INFO(...) google::RawLog__(google::GLOG_INFO, \
+                                   __FILE__, __LINE__, __VA_ARGS__)
+#else
+#define RAW_LOG_INFO(...) google::RawLogStub__(0, __VA_ARGS__)
+#endif // STRIP_LOG == 0
+
+#if STRIP_LOG <= 1
+#define RAW_LOG_WARNING(...) google::RawLog__(google::GLOG_WARNING,   \
+                                      __FILE__, __LINE__, __VA_ARGS__)
+#else
+#define RAW_LOG_WARNING(...) google::RawLogStub__(0, __VA_ARGS__)
+#endif // STRIP_LOG <= 1
+
+#if STRIP_LOG <= 2
+#define RAW_LOG_ERROR(...) google::RawLog__(google::GLOG_ERROR,       \
+                                    __FILE__, __LINE__, __VA_ARGS__)
+#else
+#define RAW_LOG_ERROR(...) google::RawLogStub__(0, __VA_ARGS__)
+#endif // STRIP_LOG <= 2
+
+#if STRIP_LOG <= 3
+#define RAW_LOG_FATAL(...) google::RawLog__(google::GLOG_FATAL,       \
+                                    __FILE__, __LINE__, __VA_ARGS__)
+#else
+#define RAW_LOG_FATAL(...) \
+  do { \
+    google::RawLogStub__(0, __VA_ARGS__);        \
+    exit(1); \
+  } while (0)
+#endif // STRIP_LOG <= 3
+
+// Similar to CHECK(condition) << message,
+// but for low-level modules: we use only RAW_LOG that does not allocate memory.
+// We do not want to provide args list here to encourage this usage:
+//   if (!cond)  RAW_LOG(FATAL, "foo ...", hard_to_compute_args);
+// so that the args are not computed when not needed.
+#define RAW_CHECK(condition, message)                                   \
+  do {                                                                  \
+    if (!(condition)) {                                                 \
+      RAW_LOG(FATAL, "Check %s failed: %s", #condition, message);       \
+    }                                                                   \
+  } while (0)
+
+// Debug versions of RAW_LOG and RAW_CHECK
+#ifndef NDEBUG
+
+#define RAW_DLOG(severity, ...) RAW_LOG(severity, __VA_ARGS__)
+#define RAW_DCHECK(condition, message) RAW_CHECK(condition, message)
+
+#else  // NDEBUG
+
+#define RAW_DLOG(severity, ...)                                 \
+  while (false)                                                 \
+    RAW_LOG(severity, __VA_ARGS__)
+#define RAW_DCHECK(condition, message) \
+  while (false) \
+    RAW_CHECK(condition, message)
+
+#endif  // NDEBUG
+
+// Stub log function used to work around for unused variable warnings when
+// building with STRIP_LOG > 0.
+static inline void RawLogStub__(int /* ignored */, ...) {
+}
+
+// Helper function to implement RAW_LOG and RAW_VLOG
+// Logs format... at "severity" level, reporting it
+// as called from file:line.
+// This does not allocate memory or acquire locks.
+GOOGLE_GLOG_DLL_DECL void RawLog__(LogSeverity severity,
+                                   const char* file,
+                                   int line,
+                                   const char* format, ...)
+   ;
+
+}
+
+#endif  // BASE_RAW_LOGGING_H_

x86_64-ubuntu1604/include/googleglog/stl_logging.h

+// Copyright (c) 2003, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Stream output operators for STL containers; to be used for logging *only*.
+// Inclusion of this file lets you do:
+//
+// list<string> x;
+// LOG(INFO) << "data: " << x;
+// vector<int> v1, v2;
+// CHECK_EQ(v1, v2);
+//
+// If you want to use this header file with hash maps or slist, you
+// need to define macros before including this file:
+//
+// - GLOG_STL_LOGGING_FOR_UNORDERED     - <unordered_map> and <unordered_set>
+// - GLOG_STL_LOGGING_FOR_TR1_UNORDERED - <tr1/unordered_(map|set)>
+// - GLOG_STL_LOGGING_FOR_EXT_HASH      - <ext/hash_(map|set)>
+// - GLOG_STL_LOGGING_FOR_EXT_SLIST     - <ext/slist>
+//
+
+#ifndef UTIL_GTL_STL_LOGGING_INL_H_
+#define UTIL_GTL_STL_LOGGING_INL_H_
+
+#if !1
+# error We do not support stl_logging for this compiler
+#endif
+
+#include <deque>
+#include <list>
+#include <map>
+#include <ostream>
+#include <set>
+#include <utility>
+#include <vector>
+
+#ifdef GLOG_STL_LOGGING_FOR_UNORDERED
+# include <unordered_map>
+# include <unordered_set>
+#endif
+
+#ifdef GLOG_STL_LOGGING_FOR_TR1_UNORDERED
+# include <tr1/unordered_map>
+# include <tr1/unordered_set>
+#endif
+
+#ifdef GLOG_STL_LOGGING_FOR_EXT_HASH
+# include <ext/hash_set>
+# include <ext/hash_map>
+#endif
+#ifdef GLOG_STL_LOGGING_FOR_EXT_SLIST
+# include <ext/slist>
+#endif
+
+// Forward declare these two, and define them after all the container streams
+// operators so that we can recurse from pair -> container -> container -> pair
+// properly.
+template<class First, class Second>
+std::ostream& operator<<(std::ostream& out, const std::pair<First, Second>& p);
+
+namespace google {
+
+template<class Iter>
+void PrintSequence(std::ostream& out, Iter begin, Iter end);
+
+}
+
+#define OUTPUT_TWO_ARG_CONTAINER(Sequence) \
+template<class T1, class T2> \
+inline std::ostream& operator<<(std::ostream& out, \
+                                const Sequence<T1, T2>& seq) { \
+  google::PrintSequence(out, seq.begin(), seq.end()); \
+  return out; \
+}
+
+OUTPUT_TWO_ARG_CONTAINER(std::vector)
+OUTPUT_TWO_ARG_CONTAINER(std::deque)
+OUTPUT_TWO_ARG_CONTAINER(std::list)
+#ifdef GLOG_STL_LOGGING_FOR_EXT_SLIST
+OUTPUT_TWO_ARG_CONTAINER(__gnu_cxx::slist)
+#endif
+
+#undef OUTPUT_TWO_ARG_CONTAINER
+
+#define OUTPUT_THREE_ARG_CONTAINER(Sequence) \
+template<class T1, class T2, class T3> \
+inline std::ostream& operator<<(std::ostream& out, \
+                                const Sequence<T1, T2, T3>& seq) { \
+  google::PrintSequence(out, seq.begin(), seq.end()); \
+  return out; \
+}
+
+OUTPUT_THREE_ARG_CONTAINER(std::set)
+OUTPUT_THREE_ARG_CONTAINER(std::multiset)
+
+#undef OUTPUT_THREE_ARG_CONTAINER
+
+#define OUTPUT_FOUR_ARG_CONTAINER(Sequence) \
+template<class T1, class T2, class T3, class T4> \
+inline std::ostream& operator<<(std::ostream& out, \
+                                const Sequence<T1, T2, T3, T4>& seq) { \
+  google::PrintSequence(out, seq.begin(), seq.end()); \
+  return out; \
+}
+
+OUTPUT_FOUR_ARG_CONTAINER(std::map)
+OUTPUT_FOUR_ARG_CONTAINER(std::multimap)
+#ifdef GLOG_STL_LOGGING_FOR_UNORDERED
+OUTPUT_FOUR_ARG_CONTAINER(std::unordered_set)
+OUTPUT_FOUR_ARG_CONTAINER(std::unordered_multiset)
+#endif
+#ifdef GLOG_STL_LOGGING_FOR_TR1_UNORDERED
+OUTPUT_FOUR_ARG_CONTAINER(std::tr1::unordered_set)
+OUTPUT_FOUR_ARG_CONTAINER(std::tr1::unordered_multiset)
+#endif
+#ifdef GLOG_STL_LOGGING_FOR_EXT_HASH
+OUTPUT_FOUR_ARG_CONTAINER(__gnu_cxx::hash_set)
+OUTPUT_FOUR_ARG_CONTAINER(__gnu_cxx::hash_multiset)
+#endif
+
+#undef OUTPUT_FOUR_ARG_CONTAINER
+
+#define OUTPUT_FIVE_ARG_CONTAINER(Sequence) \
+template<class T1, class T2, class T3, class T4, class T5> \
+inline std::ostream& operator<<(std::ostream& out, \
+                                const Sequence<T1, T2, T3, T4, T5>& seq) { \
+  google::PrintSequence(out, seq.begin(), seq.end()); \
+  return out; \
+}
+
+#ifdef GLOG_STL_LOGGING_FOR_UNORDERED
+OUTPUT_FIVE_ARG_CONTAINER(std::unordered_map)
+OUTPUT_FIVE_ARG_CONTAINER(std::unordered_multimap)
+#endif
+#ifdef GLOG_STL_LOGGING_FOR_TR1_UNORDERED
+OUTPUT_FIVE_ARG_CONTAINER(std::tr1::unordered_map)
+OUTPUT_FIVE_ARG_CONTAINER(std::tr1::unordered_multimap)
+#endif
+#ifdef GLOG_STL_LOGGING_FOR_EXT_HASH
+OUTPUT_FIVE_ARG_CONTAINER(__gnu_cxx::hash_map)
+OUTPUT_FIVE_ARG_CONTAINER(__gnu_cxx::hash_multimap)
+#endif
+
+#undef OUTPUT_FIVE_ARG_CONTAINER
+
+template<class First, class Second>
+inline std::ostream& operator<<(std::ostream& out,
+                                const std::pair<First, Second>& p) {
+  out << '(' << p.first << ", " << p.second << ')';
+  return out;
+}
+
+namespace google {
+
+template<class Iter>
+inline void PrintSequence(std::ostream& out, Iter begin, Iter end) {
+  // Output at most 100 elements -- appropriate if used for logging.
+  for (int i = 0; begin != end && i < 100; ++i, ++begin) {
+    if (i > 0) out << ' ';
+    out << *begin;
+  }
+  if (begin != end) {
+    out << " ...";
+  }
+}
+
+}
+
+// Note that this is technically undefined behavior! We are adding things into
+// the std namespace for a reason though -- we are providing new operations on
+// types which are themselves defined with this namespace. Without this, these
+// operator overloads cannot be found via ADL. If these definitions are not
+// found via ADL, they must be #included before they're used, which requires
+// this header to be included before apparently independent other headers.
+//
+// For example, base/logging.h defines various template functions to implement
+// CHECK_EQ(x, y) and stream x and y into the log in the event the check fails.
+// It does so via the function template MakeCheckOpValueString:
+//   template<class T>
+//   void MakeCheckOpValueString(strstream* ss, const T& v) {
+//     (*ss) << v;
+//   }
+// Because 'glog/logging.h' is included before 'glog/stl_logging.h',
+// subsequent CHECK_EQ(v1, v2) for vector<...> typed variable v1 and v2 can only
+// find these operator definitions via ADL.
+//
+// Even this solution has problems -- it may pull unintended operators into the
+// namespace as well, allowing them to also be found via ADL, and creating code
+// that only works with a particular order of includes. Long term, we need to
+// move all of the *definitions* into namespace std, bet we need to ensure no
+// one references them first. This lets us take that step. We cannot define them
+// in both because that would create ambiguous overloads when both are found.
+namespace std { using ::operator<<; }
+
+#endif  // UTIL_GTL_STL_LOGGING_INL_H_

x86_64-ubuntu1604/include/googleglog/vlog_is_on.h

+// Copyright (c) 1999, 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: Ray Sidney and many others
+//
+// Defines the VLOG_IS_ON macro that controls the variable-verbosity
+// conditional logging.
+//
+// It's used by VLOG and VLOG_IF in logging.h
+// and by RAW_VLOG in raw_logging.h to trigger the logging.
+//
+// It can also be used directly e.g. like this:
+//   if (VLOG_IS_ON(2)) {
+//     // do some logging preparation and logging
+//     // that can't be accomplished e.g. via just VLOG(2) << ...;
+//   }
+//
+// The truth value that VLOG_IS_ON(level) returns is determined by 
+// the three verbosity level flags:
+//   --v=<n>  Gives the default maximal active V-logging level;
+//            0 is the default.
+//            Normally positive values are used for V-logging levels.
+//   --vmodule=<str>  Gives the per-module maximal V-logging levels to override
+//                    the value given by --v.
+//                    E.g. "my_module=2,foo*=3" would change the logging level
+//                    for all code in source files "my_module.*" and "foo*.*"
+//                    ("-inl" suffixes are also disregarded for this matching).
+//
+// SetVLOGLevel helper function is provided to do limited dynamic control over
+// V-logging by overriding the per-module settings given via --vmodule flag.
+//
+// CAVEAT: --vmodule functionality is not available in non gcc compilers.
+//
+
+#ifndef BASE_VLOG_IS_ON_H_
+#define BASE_VLOG_IS_ON_H_
+
+#include "glog/log_severity.h"
+
+// Annoying stuff for windows -- makes sure clients can import these functions
+#ifndef GOOGLE_GLOG_DLL_DECL
+# if defined(_WIN32) && !defined(__CYGWIN__)
+#   define GOOGLE_GLOG_DLL_DECL  __declspec(dllimport)
+# else
+#   define GOOGLE_GLOG_DLL_DECL
+# endif
+#endif
+
+#if defined(__GNUC__)
+// We emit an anonymous static int* variable at every VLOG_IS_ON(n) site.
+// (Normally) the first time every VLOG_IS_ON(n) site is hit,
+// we determine what variable will dynamically control logging at this site:
+// it's either FLAGS_v or an appropriate internal variable
+// matching the current source file that represents results of
+// parsing of --vmodule flag and/or SetVLOGLevel calls.
+#define VLOG_IS_ON(verboselevel)                                \
+  __extension__  \
+  ({ static google::int32* vlocal__ = &google::kLogSiteUninitialized;           \
+     google::int32 verbose_level__ = (verboselevel);                    \
+     (*vlocal__ >= verbose_level__) &&                          \
+     ((vlocal__ != &google::kLogSiteUninitialized) ||                   \
+      (google::InitVLOG3__(&vlocal__, &FLAGS_v,                         \
+                   __FILE__, verbose_level__))); })
+#else
+// GNU extensions not available, so we do not support --vmodule.
+// Dynamic value of FLAGS_v always controls the logging level.
+#define VLOG_IS_ON(verboselevel) (FLAGS_v >= (verboselevel))
+#endif
+
+// Set VLOG(_IS_ON) level for module_pattern to log_level.
+// This lets us dynamically control what is normally set by the --vmodule flag.
+// Returns the level that previously applied to module_pattern.
+// NOTE: To change the log level for VLOG(_IS_ON) sites
+//	 that have already executed after/during InitGoogleLogging,
+//	 one needs to supply the exact --vmodule pattern that applied to them.
+//       (If no --vmodule pattern applied to them
+//       the value of FLAGS_v will continue to control them.)
+extern GOOGLE_GLOG_DLL_DECL int SetVLOGLevel(const char* module_pattern,
+                                             int log_level);
+
+// Various declarations needed for VLOG_IS_ON above: =========================
+
+// Special value used to indicate that a VLOG_IS_ON site has not been
+// initialized.  We make this a large value, so the common-case check
+// of "*vlocal__ >= verbose_level__" in VLOG_IS_ON definition
+// passes in such cases and InitVLOG3__ is then triggered.
+extern google::int32 kLogSiteUninitialized;
+
+// Helper routine which determines the logging info for a particalur VLOG site.
+//   site_flag     is the address of the site-local pointer to the controlling
+//                 verbosity level
+//   site_default  is the default to use for *site_flag
+//   fname         is the current source file name
+//   verbose_level is the argument to VLOG_IS_ON
+// We will return the return value for VLOG_IS_ON
+// and if possible set *site_flag appropriately.
+extern GOOGLE_GLOG_DLL_DECL bool InitVLOG3__(
+    google::int32** site_flag,
+    google::int32* site_default,
+    const char* fname,
+    google::int32 verbose_level);
+
+#endif  // BASE_VLOG_IS_ON_H_