Avoid a compile error on hosts with libevent too old for EVENT_LOG_WARN. #7016

pull gmaxwell wants to merge 1 commits into bitcoin:master from gmaxwell:without_EVENT_LOG_WARN changing 1 files +4 −0

gmaxwell commented at 1:57 PM on November 14, 2015: contributor

This means that some low priority libevent errors may get logged with debugging disabled when they wouldn't otherwise. In a quick check it did not appear to be chatty.
gmaxwell commented at 1:59 PM on November 14, 2015: contributor

Not the end of the world if this isn't wanted; it's needed on Fedora 19, and (I think) Fedora 20 which some of my old test hosts are still running and I was tired of patching around it locally. Seems like a mostly harmless compatibility boost.
in src/httpserver.cpp:None in 4e5cb8bab2 outdated
```
 370 |          LogPrintf("libevent: %s\n", msg);
 371 |      else
 372 |          LogPrint("libevent", "libevent: %s\n", msg);
 373 | +#else
 374 | +    // EVENT_LOG_WARN was added in 2.0.19; so in some older systems libevent warnings won't be debug-only.
 375 | +    LogPrint("libevent: %s\n", msg);
```
morcos commented at 6:43 PM on November 14, 2015:

What does LogPrint without a category do? Did you mean this to be LogPrintf?

gmaxwell commented at 8:38 PM on November 14, 2015:

Gah. What it doesn't to is it doesn't fail to compile; so much for type safety. Good spotting; thats what I get from changing from the always debug to always no debug at the last second. :-/
petertodd commented at 7:48 PM on November 14, 2015: contributor

utACK
jonasschnelli added the label RPC on Nov 16, 2015
laanwj commented at 8:54 AM on November 16, 2015: member
Concept ACK

Though what I think is interesting here is that we have a severity argument, just not the definition of EVENT_LOG_WARN. Looking at the changelog the old (now deprecated) name for EVENT_LOG_WARN was prefixed with an underscore. Can you try:
```
#ifndef EVENT_LOG_WARN
#define EVENT_LOG_WARN _EVENT_LOG_WARN
#endif
```
BTW: If you plan on doing any benchmarking or advanced testing, please use an up to date libevent. There have been various nasty bugs fixed over time.
gmaxwell commented at 9:16 AM on November 16, 2015: contributor

Indeed, _EVENT_LOG_WARN is there and has the same definition.

Avoid a compile error on hosts with libevent too old for EVENT_LOG_WARN.

This uses _EVENT_LOG_WARN instead, which appears to be defined in the
 old versions of libevent that I have on some systems.

aee22bf288

laanwj merged this on Nov 16, 2015
laanwj closed this on Nov 16, 2015
laanwj referenced this in commit dafefb7924 on Nov 16, 2015
str4d cross-referenced this on Mar 22, 2017 from issue libevent-based http server by str4d
zkbot referenced this in commit b0afc4ba1d on Mar 22, 2017
zkbot referenced this in commit f9f48667be on Mar 25, 2017
dagurval cross-referenced this on Jul 12, 2017 from issue libevent-based http server by dagurval
bitcoin locked this on Sep 8, 2021

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