Use cppformat to implement writelogf

This represents the first use of variadic templates in Cantera.

include/cantera/base/global.h

@@ -20,6 +20,7 @@
 #define CT_GLOBAL_H
 
 #include "ct_defs.h"
+#include "cantera/ext/format.h"
 
 namespace Cantera
 {
@@ -164,7 +165,10 @@ inline void writelog(const std::string& msg, int loglevel)
  * @param fmt  c format string for the following arguments
  * @ingroup textlogs
  */
-void writelogf(const char* fmt,...);
+template <typename... Args>
+void writelogf(const char* fmt, const Args& ... args) {
+    writelog(fmt::sprintf(fmt, args...));
+}
 
 //! Write an end of line character to the screen and flush output
 void writelogendl();

src/base/global.cpp

@@ -5,9 +5,6 @@
 #include "application.h"
 #include "units.h"
 
-#include <cstdio>
-#include <stdarg.h>
-
 using namespace std;
 
 namespace Cantera
@@ -35,24 +32,6 @@ void writelog(const std::string& msg)
     app()->writelog(msg);
 }
 
-void writelogf(const char* fmt,...)
-{
-    enum { BUFSIZE = 2048 };
-    char sbuf[BUFSIZE];
-
-    va_list args;
-    va_start(args, fmt);
-
-#ifdef _MSC_VER
-    _vsnprintf(sbuf, BUFSIZE, fmt, args);
-#else
-    vsprintf(sbuf, fmt, args);
-#endif
-
-    writelog(sbuf);
-    va_end(args);
-}
-
 void writelogendl()
 {
     app()->writelogendl();