if --with-versioned is active (default), a couple of macros in pcm.c start generating some completely broken, __old-prefixed wrapper functions, which then are getting used whenever the actual function is called.
for example: snd_pcm_hw_params_set_buffer_time_near
__OLD_NEAR1(snd_pcm_hw_params_set_buffer_time_near, unsigned int);
->
#define __OLD_NEAR1(name, ret_type) __P_OLD_NEAR1(__old_, name, ret_type)
->
#define __P_OLD_NEAR1(pfx, name, ret_type) \ ret_type pfx##name(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, ret_type val, int *dir) \ { \ if (INTERNAL(name)(pcm, params, &val, dir) < 0) \ return 0; \ return (ret_type)val; \ }
this will lead to generating a function __old_snd_pcm_hw_params_set_buffer_time_near which expands to
unsigned int __old_snd_pcm_hw_params_set_buffer_time_near(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, ret_type val, int *dir) { if snd1_pcm_hw_params_set_buffer_time_near(pcm, params, &val, dir) < 0) return 0; return (ret_type)val; }
there 2 bugs in there, 1) the real function gets passed a pointer to a pointer of unsigned, which is then happily dereferenced and the original pointer used as an int, and 2) the return type logic is wrong, in case of a non-error, the original pointer will be returned instead of 0 to indicate success.
the right fix would look something like this:
@@ -7190,19 +7192,15 @@ __OLD_GET1(snd_pcm_hw_params_get_tick_time_max, unsigned int, unsigned int);
#define __P_OLD_NEAR(pfx, name, ret_type) \ -ret_type pfx##name(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, ret_type val) \ +ret_type pfx##name(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, ret_type *val) \ { \ - if (INTERNAL(name)(pcm, params, &val) < 0) \ - return 0; \ - return (ret_type)val; \ + return(INTERNAL(name)(pcm, params, val)); \ }
#define __P_OLD_NEAR1(pfx, name, ret_type) \ -ret_type pfx##name(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, ret_type val, int *dir) \ +ret_type pfx##name(snd_pcm_t *pcm, snd_pcm_hw_params_t *params, ret_type *val, int *dir) \ { \ - if (INTERNAL(name)(pcm, params, &val, dir) < 0) \ - return 0; \ - return (ret_type)val; \ + return (INTERNAL(name)(pcm, params, val, dir) < 0); \ }
#define __OLD_NEAR(name, ret_type) __P_OLD_NEAR(__old_, name, ret_type)
this is only half of the fix though, the "old" getter functions seem to misbehave as well. the misbehaviour can be inspected by using a small openal-soft (version 1.14) example code, and breaking on alsa_reset_playback and single stepping through the invocation of CHECK(snd_pcm_hw_params_set_buffer_time_near(data->pcmHandle, hp, &bufferLen, NULL));