Fix ssize_t definition. (#80)

* Fix linter.

include/rabit/internal/rabit-inl.h

@@ -1,5 +1,5 @@
 /*!
- * Copyright by Contributors
+ * Copyright (c) 2014-2019 by Contributors
  * \file rabit-inl.h
  * \brief implementation of inline template function for rabit interface
  *
@@ -188,7 +188,7 @@ inline void TrackerPrintf(const char *fmt, ...) {
   msg.resize(strlen(msg.c_str()));
   TrackerPrint(msg);
 }
-#endif
+#endif  // RABIT_STRICT_CXX98_
 // load latest check point
 inline int LoadCheckPoint(Serializable *global_model,
                           Serializable *local_model) {
@@ -323,6 +323,6 @@ inline void SerializeReducer<DType>::Allreduce(DType *sendrecvobj,
                                                std::function<void()> prepare_fun) {
   this->Allreduce(sendrecvobj, max_nbytes, count, InvokeLambda_, &prepare_fun);
 }
-#endif
+#endif  // DMLC_USE_CXX11
 }  // namespace rabit
 #endif  // RABIT_INTERNAL_RABIT_INL_H_

include/rabit/internal/timer.h

@@ -1,5 +1,5 @@
 /*!
- * Copyright by Contributors
+ * Copyright (c) 2014-2019 by Contributors
  * \file timer.h
  * \brief This file defines the utils for timing
  * \author Tianqi Chen, Nacho, Tianyi
@@ -10,7 +10,7 @@
 #ifdef __MACH__
 #include <mach/clock.h>
 #include <mach/mach.h>
-#endif
+#endif  // __MACH__
 #include "./utils.h"
 
 namespace rabit {
@@ -19,22 +19,22 @@ namespace utils {
  * \brief return time in seconds, not cross platform, avoid to use this in most places
  */
 inline double GetTime(void) {
-  #ifdef __MACH__
+#ifdef __MACH__
   clock_serv_t cclock;
   mach_timespec_t mts;
   host_get_clock_service(mach_host_self(), CALENDAR_CLOCK, &cclock);
   utils::Check(clock_get_time(cclock, &mts) == 0, "failed to get time");
   mach_port_deallocate(mach_task_self(), cclock);
   return static_cast<double>(mts.tv_sec) + static_cast<double>(mts.tv_nsec) * 1e-9;
-  #else
-  #if defined(__unix__) || defined(__linux__)
+#else
+#if defined(__unix__) || defined(__linux__)
   timespec ts;
   utils::Check(clock_gettime(CLOCK_REALTIME, &ts) == 0, "failed to get time");
   return static_cast<double>(ts.tv_sec) + static_cast<double>(ts.tv_nsec) * 1e-9;
-  #else
+#else
   return static_cast<double>(time(NULL));
-  #endif
-  #endif
+#endif  // defined(__unix__) || defined(__linux__)
+#endif  // __MACH__
 }
 }  // namespace utils
 }  // namespace rabit

include/rabit/internal/utils.h

@@ -14,32 +14,35 @@
 
 #ifndef RABIT_STRICT_CXX98_
 #include <cstdarg>
-#endif
+#endif  // RABIT_STRICT_CXX98_
 
 #if !defined(__GNUC__) || defined(__FreeBSD__)
 #define fopen64 std::fopen
-#endif
+#endif  // !defined(__GNUC__) || defined(__FreeBSD__)
+
 #ifdef _MSC_VER
 // NOTE: sprintf_s is not equivalent to snprintf,
 // they are equivalent when success, which is sufficient for our case
 #define snprintf sprintf_s
 #define vsnprintf vsprintf_s
+
 #else
+
 #ifdef _FILE_OFFSET_BITS
 #if _FILE_OFFSET_BITS == 32
 #pragma message("Warning: FILE OFFSET BITS defined to be 32 bit")
-#endif
-#endif
+#endif  // _FILE_OFFSET_BITS == 32
+#endif  // _FILE_OFFSET_BITS
 
 #ifdef __APPLE__
 #define off64_t off_t
 #define fopen64 std::fopen
-#endif
+#endif  // __APPLE__
 
 extern "C" {
 #include <sys/types.h>
 }
-#endif
+#endif  // _MSC_VER
 
 #ifdef _MSC_VER
 typedef unsigned char uint8_t;
@@ -49,7 +52,7 @@ typedef unsigned __int64 uint64_t;
 typedef __int64 int64_t;
 #else
 #include <inttypes.h>
-#endif
+#endif  // _MSC_VER
 
 namespace rabit {
 /*! \brief namespace for helper utils of the project */
@@ -88,8 +91,8 @@ inline void HandleLogPrint(const char *msg) {
 void HandleAssertError(const char *msg);
 void HandleCheckError(const char *msg);
 void HandlePrint(const char *msg);
-#endif
-#endif
+#endif  // RABIT_STRICT_CXX98_
+#endif  // RABIT_CUSTOMIZE_MSG_
 #ifdef RABIT_STRICT_CXX98_
 // these function pointers are to be assigned
 extern "C" void (*Printf)(const char *fmt, ...);
@@ -151,7 +154,7 @@ inline void Error(const char *fmt, ...) {
     HandleCheckError(msg.c_str());
   }
 }
-#endif
+#endif  // RABIT_STRICT_CXX98_
 
 /*! \brief replace fopen, report error when the file open fails */
 inline std::FILE *FopenCheck(const char *fname, const char *flag) {