Subject: [Boost-bugs] [Boost C++ Libraries] #13423: boost log misses user-defined operator<< in MSVC 2017 1.12.111.1002
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2018-01-28 10:24:49
#13423: boost log misses user-defined operator<< in MSVC 2017 1.12.111.1002
---------------------------------+-----------------------------
Reporter: matthew.malcomson@⦠| Owner: Andrey Semashev
Type: Bugs | Status: new
Milestone: To Be Determined | Component: log
Version: Boost 1.65.0 | Severity: Problem
Keywords: |
---------------------------------+-----------------------------
Defining an `operator<<` on `std::ostream` for an enum that is used as the
severity attribute in the `severity_logger_mt` source usually means that
printing the severity attribute of a record in a custom formatter uses
that override.
With some particular optimisation options in MSVC (see below), and a setup
where the function using the logging is not in the same translation unit
but takes an argument of the severity enum type this behaviour goes away
and instead the logging prints out the integer cast of that enum.
{{{
# Table of when the problem occurs under MSVC.
# the "get INFO?" column is "NO" when the problem occurs
# | Optimise References | Inline Function Expansion | Whole Program
Optimisation | get INFO? |
#
|---------------------+---------------------------+----------------------------+-----------|
# | false | disabled | false
| NO |
# | true | disabled | false
| NO |
# | false | only explicit inline | false
| YES |
# | true | only explicit inline | false
| YES |
# | false | disabled | true
| ERROR |
# | true | disabled | true
| NO |
# | false | only explicit inline | true
| ERROR |
# | true | only explicit inline | true
| NO |
}}}
I haven't been able to reproduce this behaviour on Linux under either
clang or gcc.
A zip file of the smallest problematic example I've managed to find is
attached.
In the example, most of the code is in a file called `logger.cpp`.
There are two functions in `example_project.cpp`, on is there for the
executable to see, while the other that is simply there to
On linux unzip, then make and run for both `gcc` and `clang` with `make
all`.
You can see that the severity is printed out as `INFO`.
On Windows open the `temp_solution.sln` file with MSVC, click `Build all`,
then run the resulting `example_project.exe` binary.
You can see that the severity (and some other printouts of the enum) are
printed out as `1`.
If I define an override on the `basic_record_ostream` template, then
placing an enum instance onto the logging stream picks up the override,
while the severity argument doesn't.
You can allow `Inline function expansion` under project properties ->
C/C++ -> Optimization , this then picks up the user-defined override.
In `example_project.cpp` there is a function `LogLevelFun()` that takes a
`LogLevelEnum` as an argument.
I do nothing with this function, but if it takes an integer as argument
instead of the enum then the problem goes away.
-- Ticket URL: <https://svn.boost.org/trac10/ticket/13423> Boost C++ Libraries <http://www.boost.org/> Boost provides free peer-reviewed portable C++ source libraries.
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