handle return codes, prevent segfaults

[stephenmathieson]

looks like you're not checking return codes for a lot of function calls. this will cause issues in a real-world environment.

at first glance, the following in "list.c" need to report/handle failures:

• line#15: zmalloc failing will cause segfaults here
• line#19: failing to create a mutex will cause nasal demons in every other list_ function
• line#30: no lock validation
• lines 39 & 40: no unlock/destroy validation (may segfault)
• line#49: no lock validation; may cause this operation to be non-thread-safe
• line#51: zmalloc failing will cause segfaults

...

if you like, i can fork and fix a few of these :)

[c9s]

Thanks, if you could send me a PR, that would be great! :)

[c9s]

oh I just checked, the list.c is not used for now. it was included for somewhat purpose, however it's not used. :)

[c9s]

I will remove that file later.

[stephenmathieson]

oh sorry I forgot about this. glad to hear it's not used ;)

[c9s]

@stephenmathieson no problem. it's welcomed to drop me any feedback at any time, thanks! :-)