alsa-project/alsa-lib issue #316 was edited from MIvanchev:
[The macro](https://github.com/alsa-project/alsa-lib/blob/master/include/global.h#L80):
``` #define SND_DLSYM_BUILD_VERSION(name, version) \ static struct snd_dlsym_link __SND_DLSYM_VERSION(snd_dlsym_, name, version); \ void __SND_DLSYM_VERSION(snd_dlsym_constructor_, name, version) (void) __attribute__ ((constructor)); \ void __SND_DLSYM_VERSION(snd_dlsym_constructor_, name, version) (void) { \ __SND_DLSYM_VERSION(snd_dlsym_, name, version).next = snd_dlsym_start; \ __SND_DLSYM_VERSION(snd_dlsym_, name, version).dlsym_name = # name; \ __SND_DLSYM_VERSION(snd_dlsym_, name, version).dlsym_ptr = (void *)&name; \ snd_dlsym_start = &__SND_DLSYM_VERSION(snd_dlsym_, name, version); \ } ``` should actually be ``` #define SND_DLSYM_NAME(name) #name
#define SND_DLSYM_BUILD_VERSION(name, version) \ static struct snd_dlsym_link __SND_DLSYM_VERSION(snd_dlsym_, name, version); \ void __SND_DLSYM_VERSION(snd_dlsym_constructor_, name, version) (void) __attribute__ ((constructor)); \ void __SND_DLSYM_VERSION(snd_dlsym_constructor_, name, version) (void) { \ __SND_DLSYM_VERSION(snd_dlsym_, name, version).next = snd_dlsym_start; \ __SND_DLSYM_VERSION(snd_dlsym_, name, version).dlsym_name = SND_DLSYM_NAME(name) \ __SND_DLSYM_VERSION(snd_dlsym_, name, version).dlsym_ptr = (void *)&name; \ snd_dlsym_start = &__SND_DLSYM_VERSION(snd_dlsym_, name, version); \ } ``` This is because for instance [this code](https://github.com/alsa-project/alsa-plugins/blob/master/pulse/ctl_pulse.c#L...) `SND_CTL_PLUGIN_SYMBOL(pulse);` expands to
``` SND_DLSYM_BUILD_VERSION(SND_CTL_PLUGIN_ENTRY(pulse), SND_CONTROL_DLSYM_VERSION); ``` and this expands to ``` ... __SND_DLSYM_VERSION(snd_dlsym_, name, version).dlsym_name = # SND_CTL_PLUGIN_ENTRY(pulse) ... ``` but the C preprocessor doesn't expand stringified tokens so the value of `dlsym_name` is actually `"SND_CTL_PLUGIN_ENTRY(pulse)"`.
Issue URL : https://github.com/alsa-project/alsa-lib/issues/316 Repository URL: https://github.com/alsa-project/alsa-lib