alsa-project/alsa-lib issue #197 was edited from ranj063: The math expression evaluator expects variable names to only be alpha-numeric. So if I have something like "[$DYNAMIC_PIPELINE + 2]", I get the error: ALSA lib confeval.c:263:(snd_config_evaluate_string) wrong expression '$[$DYNAMIC_PIPELINE + 2]' ALSA lib conf.c:5632:(snd_config_expand_custom) Expand error (walk): Invalid argument Failed to expand pre-processor definitions in input config Is it possible to add support for some non-alphanumeric characters in the variable names , esp '_'? I tried this change it seems to suffice: ``` diff --git a/src/confeval.c b/src/confeval.c index a971bf38..7330d67e 100644 --- a/src/confeval.c +++ b/src/confeval.c @@ -190,7 +190,7 @@ int _snd_eval_string(snd_config_t **dst, const char *s, } else { e = s + 1; while (*e) { - if (!isalnum(*e)) + if (!isalnum(*e) && (*e != '_')) break; e++; } ``` Issue URL : https://github.com/alsa-project/alsa-lib/issues/197 Repository URL: https://github.com/alsa-project/alsa-lib