initial, base LOG macro

Makefile

@@ -351,7 +351,7 @@ clean:
 # Examples
 #
 
-main: examples/main/main.cpp                                  build-info.h ggml.o llama.o common.o console.o grammar-parser.o $(OBJS)
+main: examples/main/main.cpp                                  build-info.h ggml.o llama.o common.o common/log.h console.o grammar-parser.o $(OBJS)
 	$(CXX) $(CXXFLAGS) $(filter-out %.h,$^) -o $@ $(LDFLAGS)
 	@echo
 	@echo '====  Run ./main -h for help.  ===='

common/log.h

@@ -0,0 +1,78 @@
+#pragma once
+
+#include <chrono>
+
+// Specifies a log target.
+//  default simply prints log to stderr
+//  this can be changed, by defining LOG_TARGET
+//  like so:
+//
+//  #define LOG_TARGET (a valid FILE*)
+//  #include "log.h"
+//
+//  The log target can also be redirected to a function
+//  like so:
+//
+//  #define LOG_TARGET log_handler()
+//  #include "log.h"
+//
+//  FILE* log_handler()
+//  {
+//      return stderr;
+//  }
+//
+//  or:
+//
+//  #define LOG_TARGET log_handler("somelog.log")
+//  #include "log.h"
+//
+//  FILE* log_handler(char*filename)
+//  {
+//      (...)
+//      return fopen(...)
+//  }
+//
+#ifndef LOG_TARGET
+#define LOG_TARGET stderr
+#endif
+
+// Allows disabling timestamps.
+//  in order to disable, define LOG_NO_TIMESTAMPS
+//  like so:
+//
+//  #define LOG_NO_TIMESTAMPS
+//  #include "log.h"
+//
+#ifndef LOG_NO_TIMESTAMPS
+#define LOG_TIMESTAMP_FMT "[%lu]"
+#define LOG_TIMESTAMP_VAL , (std::chrono::duration_cast<std::chrono::duration<std::uint64_t>>(std::chrono::system_clock::now().time_since_epoch())).count()
+#else
+#define LOG_TIMESTAMP_FMT
+#define LOG_TIMESTAMP_VAL
+#endif
+
+// Allows disabling file/line/function prefix
+//  in order to disable, define LOG_NO_FILE_LINE_FUNCTION
+//  like so:
+//
+//  #define LOG_NO_FILE_LINE_FUNCTION
+//  #include "log.h"
+//
+#ifndef LOG_NO_FILE_LINE_FUNCTION
+#define LOG_FLF_FMT "[%24s:%5d][%24s] "
+#define LOG_FLF_VAL , __FILE__, __LINE__, __FUNCTION__
+#else
+#define LOG_FLF_FMT
+#define LOG_FLF_VAL
+#endif
+
+#define _LOG(str, ...)                                                                                        \
+    {                                                                                                             \
+        fprintf(LOG_TARGET, LOG_TIMESTAMP_FMT LOG_FLF_FMT str "%c" LOG_TIMESTAMP_VAL LOG_FLF_VAL, ##__VA_ARGS__); \
+        fflush(LOG_TARGET);                                                                                       \
+    }
+
+// This us a trick to bypass the silly
+// "warning: ISO C++11 requires at least one argument for the "..." in a variadic macro"
+// so we xan gave a single macro which can be called just like printf.
+#define LOG(...) _LOG(__VA_ARGS__, '\n')

examples/main/main.cpp

@@ -3,7 +3,11 @@
 #define _GNU_SOURCE
 #endif
 
+#define LOG_TARGET log_handler("asd")
+//#define LOG_NO_TIMESTAMPS
 #include "common.h"
+
+#include "log.h"
 #include "console.h"
 #include "llama.h"
 #include "build-info.h"
@@ -54,9 +58,24 @@ void sigint_handler(int signo) {
 }
 #endif
 
+inline FILE *log_handler(std::string s)
+{
+    static bool initialized{false};
+
+    if (!initialized)[[unlikely]]
+    {
+        fprintf(stderr,"arg: %s", s.c_str());
+        initialized=true;
+    }
+
+    return stderr;
+}
+
 int main(int argc, char ** argv) {
     gpt_params params;
 
+    LOG("Hello World!")
+
     if (gpt_params_parse(argc, argv, params) == false) {
         return 1;
     }