Log to stderr by default

The logging we do use atm inside the library is largely
to spot application errors. Log that to stderr by default so
it doesn't get lost.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>

diff --git a/libevdev/libevdev.c b/libevdev/libevdev.c
index dcf2beb666923429689a7a5b8650134f3a2249e7..aa5cbd667edbf91b0dc12afee808e57fc00eb6e4 100644 (file)
--- a/libevdev/libevdev.c
+++ b/libevdev/libevdev.c
@@ -49,11 +49,32 @@ init_event_queue(struct libevdev *dev)
 }
 
 static void
-libevdev_noop_log_func(enum libevdev_log_priority priority,
+libevdev_dflt_log_func(enum libevdev_log_priority priority,
                       void *data,
                       const char *file, int line, const char *func,
                       const char *format, va_list args)
 {
+       const char *prefix;
+       switch(priority) {
+               case LIBEVDEV_LOG_ERROR: prefix = "libevdev error"; break;
+               case LIBEVDEV_LOG_INFO: prefix = "libevdev info"; break;
+               case LIBEVDEV_LOG_DEBUG:
+                                       prefix = "libevdev debug";
+                                       break;
+               default:
+                                       break;
+       }
+       /* default logging format:
+          libevev error in libevdev_some_func: blah blah
+          libevev info in libevdev_some_func: blah blah
+          libevev debug in file.c:123:libevdev_some_func: blah blah
+        */
+
+       fprintf(stderr, "%s in ", prefix);
+       if (priority == LIBEVDEV_LOG_DEBUG)
+               fprintf(stderr, "%s:%d:", file, line);
+       fprintf(stderr, "%s: ", func);
+       vfprintf(stderr, format, args);
 }
 
 /*
@@ -61,7 +82,7 @@ libevdev_noop_log_func(enum libevdev_log_priority priority,
  */
 struct logdata log_data = {
        LIBEVDEV_LOG_INFO,
-       libevdev_noop_log_func,
+       libevdev_dflt_log_func,
        NULL,
 };
 
@@ -73,6 +94,9 @@ log_msg(enum libevdev_log_priority priority,
 {
        va_list args;
 
+       if (!log_data.handler)
+               return;
+
        va_start(args, format);
        log_data.handler(priority, data, file, line, func, format, args);
        va_end(args);
@@ -137,7 +161,7 @@ libevdev_set_log_handler(struct libevdev *dev, libevdev_log_func_t logfunc)
 LIBEVDEV_EXPORT void
 libevdev_set_log_function(libevdev_log_func_t logfunc, void *data)
 {
-       log_data.handler = logfunc ? logfunc : libevdev_noop_log_func;
+       log_data.handler = logfunc;
        log_data.userdata = data;
 }
 

diff --git a/libevdev/libevdev.h b/libevdev/libevdev.h
index 36ecdd100280ff91b15d157ccde8f4976653dfe1..844a1ebe3f915bb33630f0d426105c0e6fe457c1 100644 (file)
--- a/libevdev/libevdev.h
+++ b/libevdev/libevdev.h
@@ -377,10 +377,10 @@ typedef void (*libevdev_log_func_t)(enum libevdev_log_priority priority,
 
 /**
  * Set a printf-style logging handler for library-internal logging. The default
- * logging function is a noop.
+ * logging function is to stdout.
  *
  * @param logfunc The logging function for this device. If NULL, the current
- * logging function is unset.
+ * logging function is unset and no logging is performed.
  * @param data User-specific data passed to the log handler.
  *
  * @note This function may be called before libevdev_set_fd().