Logging¶

Libtropic contains a logging functionality, which is disabled by default (unless you compile tests or examples).

You may find it useful to enable logging during libtropic evaluation or integration. There are five logging levels:

• none (default unless compiling tests or examples),
• error,
• warning,
• info,
• debug.

One of these logging levels can be switched on using the CMake switch -DLT_LOG_LVL, which is passed to cmake when building the project. The following table summarizes all logging levels and a switch corresponding to each level:

How to Log¶

Logging can be done using logging macros, which are defined in include/libtropic_logging.h. Following logging macros are available:

• LT_LOG_INFO,
• LT_LOG_WARN,
• LT_LOG_ERROR,
• LT_LOG_DEBUG.

Each macro corresponds to a verbosity level, which is activated with the aforementioned CMake switch. Macros have the same interface as the printf function, as they are essentially a wrapper over printf.

This is safe (using lt_ret_verbose() helper function only):

LT_LOG_INFO("Error code: %d, error string: %s", ret, lt_ret_verbose(ret));

This is unsafe — lt_init() will never run if logging is disabled:

LT_LOG_INFO("Initializing handle: %d", lt_init(&h));

Correct approach — call the function first, then log its result:

int ret = lt_init(&h);
LT_LOG_INFO("Initializing handle: %d", ret);