The Dlog API provides functions for sending log output.

Required Header

#include <dlog.h>

Overview

Sending log message to circular buffer. Dlog APIs include Priority and Tag. By using priority and Tag, we can easily filtered messages what we want to see.

priority

priority level indicates the urgency of log message

Macro example for useful usage

The Dlog APIs can be used by defining own macros. The macros can be defined like below examples. Thus, developers can use appropriate method as a matter of convenience.

#undef LOG_TAG
#define LOG_TAG "APP_TAG"

#define LOGI(fmt, arg...) \
    ({ do { \
        dlog_print(DLOG_INFO, LOG_TAG, "%s: %s(%d) > " fmt, __MODULE__, __func__, __LINE__, ##arg); \
    } while (0); })
#define LOGW(fmt, arg...) \
    ({ do { \
        dlog_print(DLOG_WARN, LOG_TAG, "%s: %s(%d) > " fmt, __MODULE__, __func__, __LINE__, ##arg); \
    } while (0); })
#define LOGE(fmt, arg...) \
    ({ do { \
        dlog_print(DLOG_ERROR, LOG_TAG, "%s: %s(%d) > " fmt, __MODULE__, __func__, __LINE__, ##arg); \
    } while (0); })

Signal

For technical reasons, libdlog blocks the SIGPIPE signal on initialization. If you need to receive it, feel free to reenable it, but note that you may receive the SIGPIPE signal spuriously when writing logs.

dlogutil CLI

dlogutil is a utility that can be utilized to read stored logs.

The most rudimentary way to use it is to run it with no parameters; it then prints all stored logs to the standard output and awaits more.

Parameters exist to change behaviour:

Additionally, you can specify filters. Filters go behind the parameters and are used to decide which logs are shown.
Each log line has priority and a tag. Filters are specified in the format TAG[:PRIO]. Only logs with given tags and priorities are shown.
You can specify * as the tag to match anything. Beware: only a single asterisk works that way, asterisk is not otherwise expanded. For example, "T*G" filter will NOT match "TAG", only literal "T*G".
If you don't specify any filter, it defaults to *:I
If you specify just * as the tag, without priority, its priority defaults to D
If you specify any other tag without priority, the priority defaults to V

dlogutil allows you to specify buffers. These are:

There are also priorities to be specified. These are one letter abbreviations of the following levels:

Depending on products, some of priorities (e.g., V and D) can be disabled by default to prevent too many logs.

Formats, and what they look like:

Enumeration Type Documentation

Function Documentation

#include<dlog.h>
int main(void)
{
    int integer = 21;
    char string[] = "test dlog";

    dlog_print(DLOG_INFO, "USR_TAG", "test dlog");
    dlog_print(DLOG_INFO, "USR_TAG", "%s, %d", string, integer);
    return 0;
}

#include<dlog.h>
void my_debug_print(char *format, ...)
{
    va_list ap;

    va_start(ap, format);
    dlog_vprint(DLOG_INFO, "USR_TAG", format, ap);
    va_end(ap);
}

int main(void)
{
    my_debug_print("%s", "test dlog");
    my_debug_print("%s, %d", "test dlog", 21);
    return 0;
}