Re: string file = __FILE__ considered harmful (and solution)

[Walter Bright via Digitalmars-d]

On 5/30/2018 1:27 AM, FeepingCreature wrote:
There's a very common idiom where in order to report line numbers of an error or 
a log line at the callsite of a function, you pass __FILE__ and __LINE__ as 
default parameters:

void foo(string file = __FILE__, size_t line = __LINE__);

What's wrong with this?

Say you add a string parameter, such as

void foo(string msg, string file = __FILE__, size_t line = __LINE__);

foo("Hello World");

Now when you accidentally grab an old version of the library, your new code will 
still run, but it will believe that it's being called from file "Hello World", 
line 15.

A solution:

  enum E { reserved }

  void foo(E e = E.reserved, string file = __FILE__, size_t line = __LINE__);
  void foo(string msg, E e = E.reserved, string file = __FILE__, size_t line = 
__LINE__);