Logging library for C [closed] - c

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I am looking for a productive and simple logging library for C, which can output the log to a file. Displaying messages in the log I want to make like this:
date-time tag message
It would be nice to control the level of detail of messages and control the size of the file.
I found two projects that are suitable for me. It log4c and nglogc.
log4c seemed too big. nglogc quite fit, but also has a redundant functional. maybe you tell me more variants?

Answer 1

You can use this
File logger.h
#ifndef LOGGER_H
#define LOGGER_H
void logger(const char* tag, const char* message);
#endif /* LOG_H */
File logger.c
#include "logger.h"
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
void logger(const char* tag, const char* message) {
time_t now;
time(&now);
printf("%s [%s]: %s\n", ctime(&now), tag, message);
}
It's probably not perfect, but it does satisfy the needs as you have presented them.

Answer 2

I suggest the log library which is written by myself --- zlog!
The way to fit your need in zlog is:
$ vi /etc/zlog.conf
[formats]
simple = "%D %c %m%n"
# don't know what the tag mean in your question, so put category of zlog instead
# log level is also available here, add %V means level
[rules]
my_cat.* "xxx.log"; simple
$ vi hello.c
#include <stdio.h>
#include "zlog.h"
int main(int argc, char** argv)
{
int rc;
zlog_category_t *c;
rc = dzlog_init("/etc/zlog.conf", "my_cat");
if (rc) {
printf("init failed\n");
return -1;
}
zlog_info(c, "hello, zlog");
zlog_fini();
return 0;
}
It will generate xxx.log in current directory as
2012-09-30 07:22:50 my_cat hello, zlog
Links:
Download: https://github.com/HardySimpson/zlog/archive/latest-stable.tar.gz
UsersGuide: http://hardysimpson.github.com/zlog/UsersGuide-EN.html
Hompage: http://hardysimpson.github.com/zlog/

Answer 3

Here is mine:
log.h
------
#ifndef LOG_H
#define LOG_H
void log_error(const char* message, ...); void log_info(const char* message, ...); void log_debug(const char* message, ...);
#endif
log.c
------
#include "log.h"
void log_format(const char* tag, const char* message, va_list args) { time_t now; time(&now); char * date =ctime(&now); date[strlen(date) - 1] = '\0'; printf("%s [%s] ", date, tag); vprintf(message, args); printf("\n"); }
void log_error(const char* message, ...) { va_list args; va_start(args, message); log_format("error", message, args); va_end(args); }
void log_info(const char* message, ...) { va_list args; va_start(args, message); log_format("info", message, args); va_end(args); }
void log_debug(const char* message, ...) { va_list args; va_start(args, message); log_format("debug", message, args); va_end(args); }
Have fun!

Answer 4

You can use this simple logging library:
https://github.com/kala13x/slog
Here is an example how to use:
At first you must init log. with init_log() function. First argument is log filename, second argument is log to file (1 enabled, 0 disabled) and third argument is max log level
init_slog("example", 1, 3);
print and log something
slog(0, "Test message with level 0");
slog(2, "Test message with level 2");
slog(0, "Test message with int argument: %d", int_arg);
Outout will be something like that:
2015:04:02:56 - Test message with level 0
2015:04:02:56 - Test message with level 2
2015:04:02:56 - Test message with int argument: 69

Answer 5

Take a look at the zf_log logging library. It's small, simple and provides essentials only. From README.md:
This is just a thin wrapper around sprintf() function. It provides less than 20% of functionality found in more sophisticated libraries, but covers more than 80% of common use cases. Focus is made on simplicity, ease of use and performance (to be more precise - low overhead).
Features:
Debug logging is reduced to no-op in release builds
Arguments are not evaluated when the message is not logged
No "unused" warning for variables used in log statements only
Log a memory region as HEX and ASCII
Custom output functions

Answer 6

I am also finding solutions on this problem. The answer from #edwin-buck is just simple and OK for my need.
I really know nothing on multi-threading and thread-safe, but after compiling under Visual Studio compiler (it can give some warnings and tips), and searching through google, I think a few modification might make the code above thread-safe and better.
// file log.c
void log(const char* tag, const char* message) {
time_t now;
struct tm _calendar_time;
char _buf[MAX_COUNT];
time(&now);
localtime_s(&_calendar_time, &now);
strftime(_buf, MAX_COUNT, "%c", &_calendar_time);
printf("%s [%s]: %s\n", _buf, tag, message);
}
Feel free to correct me if wrong.