Databases
StackOverflow2013
Postsdbo
POCompile time Meta-programming, with string literals
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POCompile time Meta-programming, with string literals
    primarykey
    data
    text
    <p>I'm writing some code which could really do with some simple compile time metaprogramming. It is common practise to use empty-struct tags as compile time symbols. I need to decorate the tags with some run-time config elements. static variables seem the only way to go (to enable meta-programming), however static variables require global declarations. to side step this Scott Myers suggestion (from the third edition of Effective C++), about sequencing the initialization of static variables by declaring them inside a function instead of as class variables, came to mind. </p> <p>So I came up with the following code, my hypothesis is that it will let me have a compile-time symbol with string literals use-able at runtime. I'm not missing anything I hope, and that this will work correctly, as long as I populate the runtime fields before I Initialize the depending templates classes ? .</p> <pre><code>#include &lt;string&gt; template&lt;class Instance&gt; class TheBestThing { public: static void set_name(const char * name_in) { get_name() = std::string(name_in); } static void set_fs_location(const char * fs_location_in) { get_fs_location() = std::string(fs_location_in); } static std::string &amp; get_fs_location() { static std::string fs_location; return fs_location; } static std::string &amp; get_name() { static std::string name; return name; } }; struct tag {}; typedef TheBestThing&lt;tag&gt; tbt; int main() { tbt::set_name("xyz"); tbt::set_fs_location("/etc/lala"); ImportantObject&lt;tbt&gt; SinceSlicedBread; } </code></pre> <p><strong>edit:</strong> Made community wiki.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USGeorg Fritzsche
    1. USHassan Syed
    plurals
    1. This table or related slice is empty.
    1. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POCompile time Meta-programming, with string literals
      1. USChan
      1. VTFavorite
    1. CO@Hassan: I noticed that just now. But still, you could use better tags :) -1 taken back though.
      singulars
      1. POCompile time Meta-programming, with string literals
      1. USN 1.1
    2. COthe tags are entirely appropriate for anyone looking for a question this specific.
      singulars
      1. POCompile time Meta-programming, with string literals
      1. USHassan Syed
    3. COBut what is the question?
      singulars
      1. POCompile time Meta-programming, with string literals
      1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload