Redirect stdout to stderr

- daemon: New feature for LoggingMode at /etc/dlt.conf to be able to
set value at 3 in order to redirect all stdout messages to stderr.

- libdlt: New feature for DLT_LOG_MODE environment variable to be able
to set value at 3 in order to redirect all stdout messages to stderr.

- unit test:  Add test cases for DLT_LOG_TO_STDERR

Signed-off-by: LUONG HONG DUY KHANH(RBVH/ENG42) <KHANH.LUONGHONGDUY@vn.bosch.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/include/dlt/dlt_common.h b/include/dlt/dlt_common.h
index e5e4a22..026cf75 100644
--- a/include/dlt/dlt_common.h
+++ b/include/dlt/dlt_common.h
@@ -185,7 +185,8 @@ enum {
     DLT_LOG_TO_CONSOLE = 0,
     DLT_LOG_TO_SYSLOG = 1,
     DLT_LOG_TO_FILE = 2,
-    DLT_LOG_DROPPED = 3
+    DLT_LOG_TO_STDERR = 3,
+    DLT_LOG_DROPPED = 4
 };
 
 /**
@@ -1127,10 +1128,16 @@ void dlt_log_set_filename(const char *filename);
 void dlt_log_set_level(int level);
 /**
  * Initialize (external) logging facility
- * @param mode positive, 0 = log to stdout, 1 = log to syslog, 2 = log to file
+ * @param mode positive, 0 = log to stdout, 1 = log to syslog, 2 = log to file, 3 = log to stderr
  */
 void dlt_log_init(int mode);
 /**
+ * Print with variable arguments to specified file descriptor by DLT_LOG_MODE environment variable (like fprintf)
+ * @param format format string for message
+ * @return negative value if there was an error or the total number of characters written is returned on success
+ */
+int dlt_user_printf(const char *format, ...);
+/**
  * Log ASCII string with null-termination to (external) logging facility
  * @param prio priority (see syslog() call)
  * @param s Pointer to ASCII string with null-termination