c - 如何正确关闭和释放ALSA资源

Question

如何正确关闭和释放 ALSA(和硬件参数)资源？我找到了很多例子。一切都不同。都有memleak。

例如:

#include <stdio.h>
#include <unistd.h>
#include <alsa/asoundlib.h>

int
main()
{
    snd_pcm_t *dev;

    snd_pcm_open(&dev, "default", SND_PCM_STREAM_PLAYBACK, 0);
    snd_pcm_close(dev);

    return 0;
}

Valgrind 报告:

==19586== LEAK SUMMARY:
==19586==    definitely lost: 0 bytes in 0 blocks
==19586==    indirectly lost: 0 bytes in 0 blocks
==19586==      possibly lost: 65,525 bytes in 2,020 blocks
==19586==    still reachable: 298 bytes in 6 blocks
==19586==         suppressed: 0 bytes in 0 blocks
==19586== Reachable blocks (those to which a pointer was found) are not shown.
==19586== To see them, rerun with: --leak-check=full --show-reachable=yes
==19586== 
==19586== ERROR SUMMARY: 116 errors from 116 contexts (suppressed: 4 from 4)
--19586-- 
--19586-- used_suppression:      2 dl-hack3-cond-1
--19586-- used_suppression:      2 glibc-2.5.x-on-SUSE-10.2-(PPC)-2a
==19586== 
==19586== ERROR SUMMARY: 116 errors from 116 contexts (suppressed: 4 from 4)

更新:

如果没有 snd_pcm_close()，我们会从 117 个上下文中得到 117 个错误 )))

Answer 1

如果在 snd_pcm_close(handle); 之后调用 snd_config_update_free_global() 释放全局配置，则不会出现泄漏