picolog

picolog is a minimal, yet flexible logging framework written in C99.

Features:

Written in pure C99, but compatible with C++
Only two files (header/source) for easy integration into any build system
Tiny memory and code footprint
Simple and minimalistic API
Flexible and extensible appender handling
Ability to set logging level (TRACE, DEBUG, INFO, WARN, ERROR, and FATAL)
Ability to toggle date/time, log level, filename/line, and function reporting on a per appender basis
MIT licensed

API:

plog_enable()

Enables logging. NOTE: Logging is enabled by default.

plog_disable()

Disables logging.

plog_set_lock(plog_lock_fn p_lock, void* p_userdata)

Registers a lock function that is called while writing to the log. NOTE: Off by default.

p_lock - The lock function
p_userdata - User data that is supplied to the lock function during execution.

plog_add_appender(p_appender, level, p_user_data)

Registers (adds appender to logger) and enables the specified appender. An appender writes a log entry to an output stream. This could be a console, a file, a network connection, etc...

p_appender - Pointer to the appender function to register. An appender function has the signature, void appender_func(const char* p_entry, void* p_user_data)
level - The logging threshold for the appender
p_user_data - A pointer supplied to the appender function when writing a log entry. This pointer is not modified by the logger. If not required, pass in NULL for this parameter

returns An identifier for the appender. This ID is valid until the appender is unregistered.

plog_add_stream(p_stream, level)

Registers an output stream appender.

stream - The output stream to write to
level - The logging threshold for the appender

returns An identifier for the appender. This ID is valid until the appender is unregistered.

plog_remove_appender(id)

Unregisters appender (removes the appender from the logger).

id - The appender to unreqister

plog_enable_appender(id)

Enables the specified appender. NOTE: Appenders are enabled by default afterregistration.

id - The appender to enable

plog_disable_appender(id)

Disables the specified appender.

id - The appender to disable

plog_set_level(id, level)

Sets the logging level. Only those messages of equal or higher priority (severity) than this value will be logged.

level - The new appender logging threshold.
id - The appender

plog_set_time_fmt(id, fmt)

Sets the appender timestamp format according to: https://man7.org/linux/man-pages/man3/strftime.3.html

id - The appender id
fmt - The time format

plog_colors_on(id)

Turns color output on for the specified appender. NOTE: Off by default. NOTE: Off by default.

id - The appender id

plog_colors_off(id)

Turns color ouput off for the specified appender.

id - The appender id

plog_timestamp_on(id)

Turns timestamp reporting on. NOTE: Off by default.

id - The appender id

plog_timestamp_off(id)

Turns timestamp reporting off for the specified appender.

id - The appender id

plog_level_on(id)

Turns log level reporting on for the specified appender. NOTE: On by default.

id - The appender id

plog_level_off(id)

Turns log level reporting off for the specified appender.

id - The appender id

plog_file_on(id)

Turns filename/line number reporting on for the specified appender. NOTE: Off by default.

id - The appender id

plog_file_off(id)

Turns filename/line number reporting off for the specified appender.

id - The appender id

plog_func_on(id)

Turns function name reporting on for the specified appender. NOTE: Off by default.

id - The appender id

plog_func_off(id)

Turns function name reporting off for the specified appender.

id - The appender id

plog_trace(fmt, args...)

Writes a TRACE level message to the log. This macro behaves identically to printf.

fmt - Message format
args... - Format specifiers

plog_debug(fmt, args...)

Writes a DEBUG level message to the log. This macro behaves identically to printf.

fmt - Message format
args... - Format specifiers

plog_info(fmt, args...)

Writes a INFO level message to the log. This macro behaves identically to printf.

fmt - Message format
args... - Format specifiers

plog_warn(fmt, args...)

Writes a WARN level message to the log. This macro behaves identically to printf.

fmt - Message format
args... - Format specifiers

plog_error(fmt, args...)

Writes a ERROR level message to the log. This macro behaves identically to printf.

fmt - Message format
args... - Format specifiers

plog_fatal(fmt, args...)

Writes a FATAL level message to the log. This macro behaves identically to printf.

fmt - Message format
args... - Format specifiers

Example:

#include <stdio.h>

#include "../picolog.h"

void appender(const char* p_msg, void* p_user_data)
{
    printf("%s\n", p_msg);
}

int main(int argc, char** argv)
{
    plog_id_t id = plog_add_appender(appender, PLOG_LEVEL_INFO, NULL);

    plog_timestamp_on(id);
    plog_file_on(id);
    plog_func_on(id);

    // Default log level is INFO

    plog_trace ("Test message: %d", 0);
    plog_debug ("Test message: %d", 1);
    plog_info  ("Test message: %d", 2);
    plog_warn  ("Test message: %d", 3);
    plog_error ("Test message: %d", 4);
    plog_fatal ("Test message: %d", 5);

    return 0;
}

Output:

29/02/20 14:35:42 INFO example1.c:20 [main] Test message: 2
29/02/20 14:35:42 WARN example1.c:21 [main] Test message: 3
29/02/20 14:35:42 ERROR example1.c:22 [main] Test message: 4
29/02/20 14:35:42 FATAL example1.c:23 [main] Test message: 5

picojs / picolog