Logging

Github Repo	C Header	C source	JS source
cesanta/mongoose-os	cs_dbg.h	cs_dbg.c

cs_log_set_level

void cs_log_set_level(enum cs_log_level level);

Set max log level to print; messages with the level above the given one will not be printed.

cs_log_set_filter

void cs_log_set_filter(const char *pattern);

Set log filter. NULL (a default) logs everything. Otherwise, function name and file name will be tested against the given pattern, and only matching messages will be printed.

For the pattern syntax, refer to mg_match_prefix() in str_util.h.

Example:

void foo(void) {
  LOG(LL_INFO, ("hello from foo"));
}

void bar(void) {
  LOG(LL_INFO, ("hello from bar"));
}

void test(void) {
  cs_log_set_filter(NULL);
  foo();
  bar();

  cs_log_set_filter("f*");
  foo();
  bar(); // Will NOT print anything

  cs_log_set_filter("bar");
  foo(); // Will NOT print anything
  bar();
}

cs_log_print_prefix

int cs_log_print_prefix(enum cs_log_level level, const char *func,
                        const char *filename);

Helper function which prints message prefix with the given level, function name func and filename. If message should be printed (accordingly to the current log level and filter), prints the prefix and returns 1, otherwise returns 0.

Clients should typically just use LOG() macro.

cs_log_set_file

void cs_log_set_file(FILE *file);

Set file to write logs into. If NULL, logs go to stderr.

cs_log_printf

void cs_log_printf(const char *fmt, ...) PRINTF_LIKE(1, 2);

Prints log to the current log file, appends "\n" in the end and flushes the stream.

LOG

#define LOG(l, x)                                                    \
  do {                                                               \
    if (cs_log_print_prefix(l, __func__, __FILE__)) cs_log_printf x; \
  } while (0)

Format and print message x with the given level l. Example:

LOG(LL_INFO, ("my info message: %d", 123));
LOG(LL_DEBUG, ("my debug message: %d", 123));

DBG

#define DBG(x) LOG(LL_VERBOSE_DEBUG, x)

Shortcut for LOG(LL_VERBOSE_DEBUG, (...))

DBG

#define DBG(x)

NDEBUG

LOG

#define LOG(l, x)
#define DBG(x)

CS_ENABLE_STDIO

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