Dne 08. 03. 21 v 13:58 Takashi Sakamoto napsal(a): > Hi Jaroslav, > > I have some concern about your commit 2cfe6addaef6[1] for alsa-lib, > > It adds new library API, 'snd_ctl_elem_id_compare()', to compare a pair of > IDs for control element. In the implementation, the API call returns 0 if > they are the same, else negative or positive numeric value according to > contents of the IDs. I just noted that I didn't fill the function doc text correctly. > > My concerns are: > > 1. evaluation of numid field is not covered. > > This is not preferable since ALSA control core implementation covers two > types of comparison; numid only, and the combination iface, device, > subdevice, name, and index fields. If the API is produced for general use > cases, it should correctly handle the numid-only case, in my opinion. My motivation was to allow to use this function for qsort() for example. The numid and full-field comparisons are two very different things. > 2. tri-state return value is semantically inconsistent It's correct for the sorting (strcmp like). > The ID structure includes three types of values; integer, enumeration, and > string. In my opinion, tri-state return value from them has different meaning > each other. True, the signess is the key, the value should be ignored. > The reason I post this message instead of posting any fix is that the fix > to the API affects to alsa-utils, in which the API is used by a patch you > applied a few days ago[2]. The patch also includes change to 'AM_PATH_ALSA' > declaration in configure.ac with bumped-up version to '1.2.5', and it > disables to rebuild alsa-utils on the latest toolchain. (alsa-lib 1.2.5 is > not released yet.) The latest alsa-lib in the git repo is already set to 1.2.5pre1, so if you upgrade alsa-lib, everything should be fine. I was a bit lazy to write a configure test and add a wrapper to alsactl to support the older alsa-lib. Jaroslav -- Jaroslav Kysela <perex@xxxxxxxx> Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
