third_party_alsa-lib/NOTES
Takashi Iwai 87ec7df91d Read $LIBASOUND_DEBUG as integer
Read $LIBASOUND_DEBUG as integer, 1 = hw_params dump, 2 = assert.
2005-04-20 14:26:49 +00:00

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Old versus new PCM API (values returned using indirect pointers)
================================================================
From the binary compatibility view, there is no change. For compilation,
1.0 ALSA applications do not need any change. The older applications must
use this include sequence:
#define ALSA_PCM_OLD_HW_PARAMS_API
#define ALSA_PCM_OLD_SW_PARAMS_API
#include <alsa/asoundlib.h>
If you use already the new API, you may remove old defines selecting
this API, because they are no longer used:
#define ALSA_PCM_NEW_HW_PARAMS_API
#define ALSA_PCM_NEW_SW_PARAMS_API
Verbose Error Messages
======================
Since version 1.0.8, assert() for some non-fatal errors are removed
and error messages are no longer shown to stderr as default. Instead,
the error messages appear only when the environment variable
LIBASOUND_DEBUG is set (to a non-empty value).
When LIBASOUND_DEBUG=1 is set, the errors in hw_params configuration
will be dumped to stderr. Note that this will show even the non-fatal
errors of plug layer (trial-and-error of parameters).
When LIBASOUND_DEBUG=2 is set, the default error message handler calls
assert() to catch with a debugger, in addition to parameter debugging.
This feature is disabled when --with-debug=no is passed to configure,
i.e. no strict checking is done in alsa-lib.