log: accept when applications void the log callback

Common support code in the libsigrok library passes all output through
an application specified log callback, while a default callback exists
which writes to stdout and stderr.

Accept when no callback at all is registered. Don't output text in that
case, succeed silently.

diff --git a/src/log.c b/src/log.c
index 669d442bb9c411cf2722c22bc836ac5fdf2f605f..1b01afee3368df65c02e2c847e219c59d17c16b8 100644 (file)
--- a/src/log.c
+++ b/src/log.c
@@ -260,6 +260,10 @@ SR_PRIV int sr_log(int loglevel, const char *format, ...)
        if (loglevel > cur_loglevel)
                return SR_OK;
 
+       /* Silently succeed when no logging callback is registered. */
+       if (!sr_log_cb)
+               return SR_OK;
+
        va_start(args, format);
        ret = sr_log_cb(sr_log_cb_data, loglevel, format, args);
        va_end(args);