diff --git a/example/example.cpp b/example/example.cpp
index 99c18993..692f8e9a 100644
--- a/example/example.cpp
+++ b/example/example.cpp
@@ -108,7 +108,7 @@ void async_example()
 //syslog example (linux/osx/freebsd)
 void syslog_example()
 {
-#if defined (__linux__) || defined(__APPLE__)  || defined(__FreeBSD__)
+#ifdef SPDLOG_ENABLE_SYSLOG
     std::string ident = "spdlog-example";
     auto syslog_logger = spd::syslog_logger("syslog", ident, LOG_PID);
     syslog_logger->warn("This is warning that will end up in syslog.");
diff --git a/include/spdlog/common.h b/include/spdlog/common.h
index 490deec7..7885292e 100644
--- a/include/spdlog/common.h
+++ b/include/spdlog/common.h
@@ -37,6 +37,16 @@
 #define DEPRECATED
 #endif
 
+#include <spdlog/tweakme.h>
+
+#ifndef SPDLOG_ENABLE_SYSLOG
+#if defined (__linux__) || defined(__APPLE__)  || defined(__FreeBSD__)
+#define SPDLOG_ENABLE_SYSLOG
+#elif defined(sun) || defined(__sun)
+#define SPDLOG_ENABLE_SYSLOG
+#endif
+#endif
+
 
 #include <spdlog/fmt/fmt.h>
 
diff --git a/include/spdlog/details/os.h b/include/spdlog/details/os.h
index ccadaea3..a6fbf6d9 100644
--- a/include/spdlog/details/os.h
+++ b/include/spdlog/details/os.h
@@ -198,12 +198,12 @@ inline size_t filesize(FILE *f)
         throw spdlog_ex("Failed getting file size. fd is null");
 #ifdef _WIN32
     int fd = _fileno(f);
-#if _WIN64 //64 bits        
+#if _WIN64 //64 bits
     struct _stat64 st;
     if (_fstat64(fd, &st) == 0)
         return st.st_size;
 
-#else //windows 32 bits     
+#else //windows 32 bits
     struct _stat st;
     if (_fstat(fd, &st) == 0)
         return st.st_size;
@@ -216,7 +216,7 @@ inline size_t filesize(FILE *f)
     struct stat64 st;
     if (fstat64(fd, &st) == 0)
         return st.st_size;
-#else // unix 32 bits or osx    
+#else // unix 32 bits or osx
     struct stat st;
     if (fstat(fd, &st) == 0)
         return st.st_size;
@@ -250,7 +250,42 @@ inline int utc_minutes_offset(const std::tm& tm = details::os::localtime())
         offset -= tzinfo.StandardBias;
     return offset;
 #else
-    return static_cast<int>(tm.tm_gmtoff / 60);
+    long int offset_seconds;
+
+#if defined(sun) || defined(__sun)
+    // 'tm_gmtoff' field is BSD extension and it's missing on SunOS/Solaris
+    struct helper {
+        static long int calculate_gmt_offset(const std::tm & localtm = details::os::localtime(), const std::tm & gmtm = details::os::gmtime()) {
+            int local_year = localtm.tm_year + (1900 - 1);
+            int gmt_year = gmtm.tm_year + (1900 - 1);
+
+            long int days = (
+                // difference in day of year
+                localtm.tm_yday - gmtm.tm_yday
+
+                // + intervening leap days
+                + ((local_year >> 2) - (gmt_year >> 2))
+                - (local_year / 100 - gmt_year / 100)
+                + ((local_year / 100 >> 2) - (gmt_year / 100 >> 2))
+
+                // + difference in years * 365 */
+                + (long int)(local_year - gmt_year) * 365
+            );
+
+            long int hours = (24 * days) + (localtm.tm_hour - gmtm.tm_hour);
+            long int mins = (60 * hours) + (localtm.tm_min - gmtm.tm_min);
+            long int secs = (60 * mins) + (localtm.tm_sec - gmtm.tm_sec);
+
+            return secs;
+        }
+    };
+
+    offset_seconds = helper::calculate_gmt_offset(tm);
+#else
+    offset_seconds = tm.tm_gmtoff;
+#endif
+
+    return static_cast<int>(offset_seconds / 60);
 #endif
 }
 
@@ -269,7 +304,7 @@ inline size_t thread_id()
     long tid;
     thr_self(&tid);
     return static_cast<size_t>(tid);
-#else //Default to standard C++11 (OSX and other Unix)	
+#else //Default to standard C++11 (OSX and other Unix)
     return static_cast<size_t>(std::hash<std::thread::id>()(std::this_thread::get_id()));
 #endif
 
diff --git a/include/spdlog/details/spdlog_impl.h b/include/spdlog/details/spdlog_impl.h
index b6ba5ad0..4ef085b6 100644
--- a/include/spdlog/details/spdlog_impl.h
+++ b/include/spdlog/details/spdlog_impl.h
@@ -96,7 +96,7 @@ inline std::shared_ptr<spdlog::logger> spdlog::stderr_logger_st(const std::strin
     return create_console_logger(logger_name, sinks::stderr_sink_st::instance(), color);
 }
 
-#if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__)
+#ifdef SPDLOG_ENABLE_SYSLOG
 // Create syslog logger
 inline std::shared_ptr<spdlog::logger> spdlog::syslog_logger(const std::string& logger_name, const std::string& syslog_ident, int syslog_option)
 {
diff --git a/include/spdlog/sinks/syslog_sink.h b/include/spdlog/sinks/syslog_sink.h
index 1c571ef7..4c5b6876 100644
--- a/include/spdlog/sinks/syslog_sink.h
+++ b/include/spdlog/sinks/syslog_sink.h
@@ -5,10 +5,11 @@
 
 #pragma once
 
-#if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__)
+#include <spdlog/common.h>
+
+#ifdef SPDLOG_ENABLE_SYSLOG
 
 #include <spdlog/sinks/sink.h>
-#include <spdlog/common.h>
 #include <spdlog/details/log_msg.h>
 
 #include <array>
diff --git a/include/spdlog/spdlog.h b/include/spdlog/spdlog.h
index 8a0ba08f..ff1b6022 100644
--- a/include/spdlog/spdlog.h
+++ b/include/spdlog/spdlog.h
@@ -98,7 +98,7 @@ std::shared_ptr<logger> stderr_logger_st(const std::string& logger_name, bool co
 //
 // Create and register a syslog logger
 //
-#if defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__)
+#ifdef SPDLOG_ENABLE_SYSLOG
 std::shared_ptr<logger> syslog_logger(const std::string& logger_name, const std::string& ident = "", int syslog_option = 0);
 #endif
 
diff --git a/include/spdlog/tweakme.h b/include/spdlog/tweakme.h
index 1738fb93..64bad92f 100644
--- a/include/spdlog/tweakme.h
+++ b/include/spdlog/tweakme.h
@@ -11,6 +11,14 @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 
+///////////////////////////////////////////////////////////////////////////////
+// By default, syslog sink is only enabled on tested operating systems.
+// Uncomment to enable it unconditionally.
+//
+// #define SPDLOG_ENABLE_SYSLOG
+///////////////////////////////////////////////////////////////////////////////
+
+
 ///////////////////////////////////////////////////////////////////////////////
 // Under Linux, the much faster CLOCK_REALTIME_COARSE clock can be used.
 // This clock is less accurate - can be off by dozens of millis - depending on the kernel HZ.