dmi_set_logger

Synopsis

#include <opendmi/context.h>

bool dmi_set_logger(dmi_context_t *context, dmi_log_t *logger);

Description

The dmi_set_logger function sets the handler the messages of the context are written to, see dmi_log. A context has no handler until one is set, and logs nothing.

The handler is a structure whose handler member is the function the messages are given to:

typedef void dmi_log_handler_fn(
        dmi_log_t       *target,
        dmi_log_level_t  level,
        const char      *format,
        va_list          args);

struct dmi_log
{
    dmi_log_handler_fn *handler;
};

The function receives the handler it belongs to, so that a handler needing data of its own, such as a level of its own or a file to write to, embeds dmi_log_t as the first member of a structure of its own, and takes the rest of it from target.

The handler belongs to the caller, which keeps it valid for as long as the context uses it, and is not freed along with the context.

Parameters

context: Context to set the handler of.
logger: Logging handler, or nullptr to stop logging.

Return value

Returns true, or false if context is nullptr.

Errors

None.

Examples

static void write_message(dmi_log_t *target, dmi_log_level_t level,
                          const char *format, va_list args)
{
    (void)target;

    fprintf(stderr, "%s: ", dmi_log_level_name(level));
    vfprintf(stderr, format, args);
    fputc('\n', stderr);
}

static dmi_log_t logger = { write_message };

dmi_set_logger(context, &logger);