{"id":217,"date":"2006-12-24T11:37:00","date_gmt":"2006-12-24T11:37:00","guid":{"rendered":"https:\/\/ahm.basfinans.com\/index.php\/2006\/12\/24\/the-simplest-logging-class-in-c\/"},"modified":"2006-12-24T11:37:00","modified_gmt":"2006-12-24T11:37:00","slug":"the-simplest-logging-class-in-c","status":"publish","type":"post","link":"https:\/\/ahm.basfinans.com\/index.php\/2006\/12\/24\/the-simplest-logging-class-in-c\/","title":{"rendered":"The Simplest Logging Class in C++"},"content":{"rendered":"

\"\"<\/a><\/p>\n

I want to create the simplest ever logging class in C++, so I created a single Log.h file and created a sample application that uses it.
\nThis was very useful in the small application I am working on.<\/p>\n

<\/p>\n

It compile with gcc and it works as expected.<\/p>\n

known problems:
the Log.write() function may make problems in multithreaded applications, in such case you must put a critical section around it.<\/span>
\n
<\/span>
\nYou are completely free to use the code as you wish. No limits.<\/p>\n

\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
\/\/main.cpp
\/\/logging header file
#include <stdio.h>
#include “log.h”<\/p>\n

LOG_DECLARE;<\/p>\n

int main()
{
\/\/initialize file logger
LOG_INIT(“main.log”);<\/p>\n

LOG_MSG(“Application initialization”);<\/p>\n

printf(“This is the applicationn”);<\/p>\n

LOG_MSG(“Application end”);<\/p>\n

}
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/<\/p>\n

Look at the Log.h file<\/p>\n

\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
\/\/log.h<\/p>\n

#ifndef __LOG_H
#define __LOG_H
\/\/It is bad to include files within other include files, but this is an exception to simplify the code
#include <stdio.h><\/p>\n

\/\/must be put in global scope and used once in all files
#define LOG_DECLARE Log __log;
\/\/used in any file need to access the log files, except the file that has LOG_DECLARE statment
#define LOG_USE(); extern Log __log;
\/\/init log files, called once in program initialization
#define LOG_INIT(fileName) do{if(fileName!= NULL)__log.init(fileName); else printf(“error init log file %s”, fileName);}while(0);<\/p>\n

\/\/here are the different levels of logging
#define LOG_VERBOSE(msg) __log.write(“verbose”, msg, __FILE__, __LINE__); \/\/detaild info
#define LOG_MSG(msg) __log.write(“msg”, msg, __FILE__, __LINE__); \/\/brief info
#define LOG_WARN(msg) __log.write(“warn”, msg, __FILE__, __LINE__); \/\/warning
#define LOG_ERR(msg) __log.write(“error”, msg, __FILE__, __LINE__); \/\/error
#define LOG_FATAL(msg) __log.write(“fatal”, msg, __FILE__, __LINE__); \/\/fatal error<\/p>\n

class Log
{
FILE *fp;
bool logOk;<\/p>\n

public:<\/p>\n

Log()
{fp = NULL;}
~Log() \/\/the destructor closes the file
{close();}<\/p>\n

void init(char *pfileName)
{ if(pfileName != NULL) {fp = fopen(pfileName, “a+”); if(fp != NULL) fseek(fp, 0, SEEK_END);} }<\/p>\n

void close()
{if(fp != NULL) fclose(fp); fp = NULL;}<\/p>\n

\/\/FIXME: A critical section is required to protect the file writing function in multithreading programms
void write(char *pType, char *pMsg, char *pFileName, int lineNo)
{ if(fp != NULL) fprintf(fp, “%st%st%st%st%dt%sn”, pType, __DATE__, __TIME__, pFileName, lineNo, pMsg); }
};<\/p>\n

#endif
<\/span><\/p>\n

From ahm507.blogspot.com<\/div>\n","protected":false},"excerpt":{"rendered":"

I want to create the simplest ever logging class in C++, so I created a single Log.h file and created a sample application that uses it. This was very useful in the small application I am working on. It compile with gcc and it works as expected. known problems:the Log.write() function may make problems in […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[21,24],"tags":[],"_links":{"self":[{"href":"https:\/\/ahm.basfinans.com\/index.php\/wp-json\/wp\/v2\/posts\/217"}],"collection":[{"href":"https:\/\/ahm.basfinans.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ahm.basfinans.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ahm.basfinans.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ahm.basfinans.com\/index.php\/wp-json\/wp\/v2\/comments?post=217"}],"version-history":[{"count":0,"href":"https:\/\/ahm.basfinans.com\/index.php\/wp-json\/wp\/v2\/posts\/217\/revisions"}],"wp:attachment":[{"href":"https:\/\/ahm.basfinans.com\/index.php\/wp-json\/wp\/v2\/media?parent=217"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ahm.basfinans.com\/index.php\/wp-json\/wp\/v2\/categories?post=217"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ahm.basfinans.com\/index.php\/wp-json\/wp\/v2\/tags?post=217"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}