Which is faster? Using PHP's cUrl library or invoking curl utility form shell_exec()

For a PHP project i have to access RESTful API. I was using curl to get familiar with the API. I can access the开发者_StackOverflow said API using both PHP's cUrl library and invoking the curl utility using PHP's shell_exec() function. Performance wise, which option would be better and why??

PS: I have my own server with root privilege.

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My cautious guess would be not too useful test snippets shows that the curl library is more performant.

Edit: A little test shows, that the library is faster, but not by much. Also, if you fetch millions of URLs, network latency will more likely be a bigger problem.

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Performance is pretty much exactly the same, because the same stuff is being executed internally. But you should use the API because it is cleaner.