Add slic macros that log once per call site

[bmhan12]

This PR:

• Adds suffixed SLIC_*_ONCE macros that are invoked once per call site.

Addresses #1685

[bmhan12]

Helper macro that the SLIC_*_ONCE macros use.

[bmhan12]

Convenience macro for testing, mainly to alleviate the tracking of __LINE__ in the original tests. It works pretty well for gcc, except...

[kennyweiss]

We can use std::source_location when we move to c++20 --- https://en.cppreference.com/w/cpp/utility/source_location.html

[bmhan12]

... clang and intel compilers have different __LINE__ behavior, I need to disable formatting here to keep the entire call to one line.
Otherwise, the observed behavior for example is something like:

  EXPECT_SLIC_LOG(
    SLIC_ERROR_IF(true, "this message is logged!"), // <-- This is the line number that is logged
    "ERROR", 
    "this message is logged!"); // <-- This is the line number the macro is checking for

The line number as far as I can tell in both instances is actually determined by the line placement of the closing parantheses ")".

Another example for future reference:

  EXPECT_SLIC_LOG(SLIC_ERROR_ROOT_IF(true,
    "this message is logged!"


    ), // <-- This is the line number that is logged
                  "ERROR",
                  "this message is logged!"
                  ); // <-- This is the line number the macro is checking for

[kennyweiss]

Thanks for adding this @bmhan12

• Please reintroduce the do { } while() to the macros
• Let's ensure that we have the right semantics for SLIC_*_IF_ONCE( false )

[kennyweiss]

Gut check -- this can call the macro multiple times, until EXP evaluates as true.
Is this the semantics we're looking for? Or should it only call the the macro once, independent of whether EXP is true/false?

[bmhan12]

this can call the macro multiple times, until EXP evaluates as true.

I think this is the behavior we want, and is what was in the original #1683 snippet.

A once-only if-check I think would be false and print nothing most of the time, unless you knew the true condition ahead of time to guarantee the first invocation prints, in which case, your SLIC_*_IF_ONCE usage is more like SLIC_*_ONCE .

[kennyweiss]

We can use std::source_location when we move to c++20 --- https://en.cppreference.com/w/cpp/utility/source_location.html

[Arlie-Capps]

Thanks for your careful work, @bmhan12 .

[rhornung67]

@bmhan12 thank you for this. Much better way to make a table in sphinx -- avoid lining up all the characters across rows and columns 🥇