Log-file-name access to check for CLI argument presence

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Change Log
 
+### Changes
+ - Move definition of kDefaultLogFileParam to public (header). This allows to check whether a log file name was specified via the commandline interface.
+
 ## [9.96.7] - 24-11-2018
 - Adds support for compiling easyloggingpp using Emscripten. This allows the library to be compiled into Javascript or WebAssembly and run in the browser while logging to the browser's Javascript console.
 

README.md

@@ -479,6 +479,13 @@ Following table will explain all command line arguments that you may use to defi
 | `--logging-flags=3`        | Sets logging flag. In example `i.e, 3`, it sets logging flag to `NewLineForContainer` and `AllowVerboseIfModuleNotSpecified`. See logging flags section above for further details and values. See macros section to disable this function.                                                                   |
 | `--default-log-file=FILE`  |Sets default log file for existing and future loggers. You may want to consider defining `ELPP_NO_DEFAULT_LOG_FILE` to prevent creation of default empty log file during pre-processing. See macros section to disable this function.                                                                           |
 
+You can check whether or not the user specified a file name via `--default-log-file=..` using the following check
+```[c]
+if (el::Helpers::commandLineArgs() != NULL 
+  && el::Helpers::commandLineArgs()->hasParamWithValue(el::base::consts::kDefaultLogFileParam))
+{ ... }
+```
+
  [![top] Goto Top](#table-of-contents)
 
 ### Configuration Macros

src/easylogging++.cc

@@ -98,9 +98,6 @@ static const char* kDefaultLogFile                         =      "myeasylog.log
 #endif // defined(ELPP_NO_DEFAULT_LOG_FILE)
 
 
-#if !defined(ELPP_DISABLE_LOG_FILE_FROM_ARG)
-static const char* kDefaultLogFileParam                    =      "--default-log-file";
-#endif  // !defined(ELPP_DISABLE_LOG_FILE_FROM_ARG)
 #if defined(ELPP_LOGGING_FLAGS_FROM_ARG)
 static const char* kLoggingFlagsParam                      =      "--logging-flags";
 #endif  // defined(ELPP_LOGGING_FLAGS_FROM_ARG)

src/easylogging++.h

@@ -740,6 +740,10 @@ static const char* kDefaultLoggerId                        =      ELPP_DEFAULT_L
 static const char* kDefaultLoggerId                        =      "default";
 #endif
 
+#if !defined(ELPP_DISABLE_LOG_FILE_FROM_ARG)
+static const char* kDefaultLogFileParam                    =      "--default-log-file";
+#endif  // !defined(ELPP_DISABLE_LOG_FILE_FROM_ARG)
+
 #if defined(ELPP_FEATURE_ALL) || defined(ELPP_FEATURE_PERFORMANCE_TRACKING)
 #ifdef ELPP_DEFAULT_PERFORMANCE_LOGGER
 static const char* kPerformanceLoggerId                    =      ELPP_DEFAULT_PERFORMANCE_LOGGER;