How can I add filename and line number to logging?

[parsley72]

My previous logging code worked like this:

#define log(pri, fmt, ...) \
    syslog(pri, "[%s:%d] " fmt, __FILE__, __LINE__, ##__VA_ARGS__)

#define log_crit(fmt, ...) log(LOG_CRIT, fmt, ##__VA_ARGS__)
#define log_err(fmt, ...) log(LOG_ERR, fmt, ##__VA_ARGS__)
#define log_warn(fmt, ...) log(LOG_WARNING, fmt, ##__VA_ARGS__)
#define log_info(fmt, ...) log(LOG_INFO, fmt, ##__VA_ARGS__)
#define log_notice(fmt, ...) log(LOG_NOTICE, fmt, ##__VA_ARGS__)
#define log_debug(fmt, ...) log(LOG_DEBUG, fmt, ##__VA_ARGS__)

I've ported this to spdlog but I've lost the filename and line number. How can I add this back in? I see in the code there's a struct called source_loc but there aren't any examples.

[parsley72]

Just seen https://github.com/gabime/spdlog/wiki/0.-FAQ#source-information-do-not-appear-when-using-custom-format. But if I use SPDLOG_INFO then do I need to set SPDLOG_ACTIVE_LEVEL at compile time or can I still adjust the logging level dynamically?

[tt4g]

Since SPDLOG_ACTIVE_LEVEL is the macro, it can be set only at compile time.

[parsley72]

Obviously, but if the debug level is built in using SPDLOG_ACTIVE_LEVEL can I still limit it dynamically using set_level()?

[tt4g]

logging macros (such as SPDLOG_ACTIVE_LEVEL, SPDLOG_INFO and SPDLOG_LOGGER_INFO) and set_level() API are evaluated at different times.

It would be more understandable to look at the definition of logging macros. These are macros that allow the preprocessor to remove unwanted logging statements.
See: https://github.com/gabime/spdlog/blob/v1.10.0/include/spdlog/spdlog.h#L278-L339

set_level() is the API for filtering log messages at runtime.

In other words, setting SPDLOG_LEVEL_TRACE to SPDLOG_ACTIVE_LEVEL will leave logging statements defined in all logging macros.
However, you can limit the log messages output by set_level().