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Short question, aka "TD;DR".

I have a, say, "1464478647000" string, that I guess is a UNIX timestamp. But surely it is a string containing a number that represents time, but not in a human readable format. How do I convert it to a time_t type so I can format it later to a formated string, like "3 minutes ago" in C++11?

Long question.

Sorry for my bad english, first of all.

I'm totally noob at C++11, and even C++; I just learnt a little of C and that was like 10 years ago, I almost forgot how it was. On my spare time, I'm trying to do a little fork of Feednix (a ncurses program, written in C++11, that acts as a Feedly client for Linux console - and looks like it's dead) so it looks more like a list (kind of how ncmpcpp or mutt look like). As the current Feednix implementation is not showing time of any post, I thought it would be nice to make it show the time it was published (as the web version of Feedly does, on its "Titles only" presentation).

The thing is that following the model of what's implemented on Feednix, I'm pulling the 'published' data as a string object (I couldn't figure how to pull it as an integer, or directly as a time_t object (seems the Json library doesn't allow to do that). Said 'published' data, says Feedly API docs, is "the timestamp, in ms, when this article was published, as reported by the RSS feed (often inaccurate)." An example of that is "1452614967000".

So how can I do to convert that string to a time_t object, so I can later format it to a string like "3 minutes ago" or "2 days ago"? Or is anything better I can do to get that formatted string (which is more likely)? Any help would be appreciated!

acidrums4
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  • 1452614967000 cannot be a `time_t` timestamp. Otherwise it would be `July 15, 48001, 01:30:00 -0400` – Sam Varshavchik May 29 '16 at 00:39
  • @Sam, it's *probably* milliseconds since, if you lop the "000" of the end, you get sometime Jan 12 this year, as opposed to sometime long after the human race may well have become extinct :-) – paxdiablo May 29 '16 at 00:47
  • What does "TD;DR" mean? Whatever happened to simple words like "summary"? – Kerrek SB May 29 '16 at 00:49
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    Too ... dopey? damn long? drab? ... didn't read? :-) – paxdiablo May 29 '16 at 00:50
  • Actually, just noticed the question *states* it's in milliseconds so my comment is superfluous. I'll leave it there as a monument to my inability to read before spewing forth rubbish :-) – paxdiablo May 29 '16 at 00:53

1 Answers1

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First, convert the number into long using strtol, then cast to time_t:

#include <cstdlib>
#include <ctime>

using namespace std; // to simplify answer

...
const char* timestr = "1464478647000";
time_t timenum = (time_t) strtol(timestr, NULL, 10);
Jerfov2
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  • You appear to be missing the step "convert to '3 minutes ago'" :-) Though, granted, you *did* say "First, ...". Also, would you need `ctime` as well? – paxdiablo May 29 '16 at 00:45
  • It is not guaranteed that `time_t` is of `long` type. On some architectures it may be 32 bit integer and your cast will cause an owerflow. – LibertyPaul May 29 '16 at 01:09
  • I think you need to use mktime() ... see "duplicate of" – 2785528 May 29 '16 at 02:32