Re: [Libevent-users] evbuffer_readln(LF) equivalent in 1.4

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Subject: Re: [Libevent-users] evbuffer_readln(LF) equivalent in 1.4

From: Nick Mathewson <nickm@xxxxxxxxxxxxx>

Date: Thu, 8 Nov 2012 12:41:26 -0500

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On Tue, Nov 6, 2012 at 11:28 PM, Tay Ray Chuan <rctay89@xxxxxxxxx> wrote:

Hi,

I'm calling evbuffer_readln(..., EVBUFFER_EOL_LF), but I have to
support 1.4 as well. Is there an equivalent invocation?
evbuffer_readline()?

I'm a little confused; looking at 1.4.14b, it appears that EVBUFFER_EOL_LF is in the source code. Maybe you mean an earlier version?

evbuffer_readline() is a deprecated synonym for EVBUFFER_EOL_ANY.

To read up to a LF character without EVBUFFER_EOL_LF in 1.4 or earlier, you could use EVBUFFER_DATA() and EVBUFFER_LENGTH() to get a get a view of the raw buffer's contents, and then use memchr to see if there is an LF character there, then drain bytes accordingly. (Don't try that in 2.0 -- the buffer is no longer implemented as a single big extent, so EVBUFFER_DATA() is no longer a remotely cheap operation.)

In addition, how do I check for the libevent version? I thought of
_EVENT_VERSION, but it looks like a string, so I can't do a

#if _EVENT_VERSION >= 1.4
...
#endif

straight up, so that's out. (Or could I?)

_EVENT_NUMERIC_VERSION seems likelier to be closer to what you want.

hth,

Nick