When a provisional patent (patent pending) is submitted it receives a time stamp. If there is already a patent claim, or someone else has an earlier time stamp then the provisional is denied (for that claim). If not, then assuming the patent office approves the claim(s), it will become a viable patent.

One exception is that if there was someone that previously developed the technology AND
was using it in the market, then they can object the provisional from becoming a patent. If they do not know about the provisional or do not object then the provisional may become a patent.