Request to direct SCR log messages to stderr or a custom file descriptor

[adammoody]

When running with SCR_DEBUG=1, SCR prints log messages to stdout. It would be useful at times to direct those messages to other files like stderr or perhaps a user-provided file descriptor. This would enable users to more easily filter SCR messages from their job logs.

The related code in SCR is in scr_err_mpi.c and scr_err_serial.c, e.g.:

scr/src/scr_err_mpi.c

Lines 52 to 63 in 48328f6

	/* print message to stdout if scr_debug is set and it is >= level */
	void scr_dbg(int level, const char *fmt, ...)
	{
	va_list argp;
	if (level == 0 || (scr_debug > 0 && scr_debug >= level)) {
	fprintf(stdout, "SCR %s: rank %d on %s: ", SCR_VERSION, scr_my_rank_world, scr_my_hostname);
	va_start(argp, fmt);
	vfprintf(stdout, fmt, argp);
	va_end(argp);
	fprintf(stdout, "\n");
	}
	}

There are a few other places where SCR calls print functions of other components, like:

scr/src/scr.c

Lines 1278 to 1289 in 48328f6

	if (scr_debug > 0 && scr_my_rank_world == 0) {
	scr_dbg(1, "Group descriptors:");
	kvtree_print_mode(scr_groupdesc_hash, 4, KVTREE_PRINT_KEYVAL);
	}
	if (scr_debug > 0 && scr_my_rank_world == 0) {
	scr_dbg(1, "Store descriptors:");
	kvtree_print_mode(scr_storedesc_hash, 4, KVTREE_PRINT_KEYVAL);
	}
	if (scr_debug > 0 && scr_my_rank_world == 0) {
	scr_dbg(1, "Redundancy descriptors:");
	kvtree_print_mode(scr_reddesc_hash, 4, KVTREE_PRINT_KEYVAL);
	}