Polyglot C# and C++ in the same file

 Programming  No Responses »
Feb 282025
 

Normally this should be impossible as the two languages are too similar and they try to interpret each other’s code as if it was there own

However both have a preprocessor of sorts which should help solve this. C++ has a full preprocessor but Csharp only has limited preprocessor capabilities with no macro substitution that greatly limits things. The preprocessor differences actually makes things harder as the CSharp compiler will error on many valid C++ processor statements.

CSharp has an annoying requirement that any line that stats with a # must be valid preprocessor statements even if in inactive preprocessor blocks which means simple things like this following code fail when logic suggests it should work

#if __cplusplus

// C++ code goes here

#include <cstdint>
#include <string>
using std::string;

#else

//CSharp code goes here
using System.Text;
using System.Collections.Generic;

#endif

The Csharp will error on the #include lines even though they are in an inactive block because they start with a #. So is there a way to include a file in C++ without starting the line with a # ? Yes, there is A C++ preprocessor statement is allowed to have white-space in front of it. The problem is so do CSharp preprocessor statements, so adding spaces or tabs before the # wont hide the preprocessor statement from the CSharp compiler. However CSharp and C++ have different ideas on what counts as white space during preprocessing. A C++ compiler converts comments into white-space in the phase before it does the preprocessing. However the CSharp compiler does not . This means adding an inline c style comment before the # is allowed in C++ and still works as a preprocessor statement. However the CSharp compiler does not see it as a preprocessor statement at all and will ignore it if it is in an inactive block which means the following rewritten code from above works when compiled by the CSharp Compiler and a C++ compiler

#if __cplusplus

// C++ code goes here

/**/#include <cstdint>
/**/#include <string>
using std::string;

#else

//CSharp code goes here
using System.Text;
using System.Collections.Generic;

#endif

This works with the CSharp 13 compiler for .Net 9.0 and earlier versions. It might not work in future versions. I don’t suggest anyone use this for anything Serious but it is interesting to know that it can be done. The /**/# trick works for any problematic C++ preprocessor statement in an inactive block, So with careful coding you can have have a class in a .cs file work as a CSharp class and an inline c++ class if you #include the .cs file in a c++project.

Files and Features in Drupal 7

 Drupal, Features  2 Responses »
Mar 122013
 

If you regularly use Features to deploy a site from dev to staging to production, you’ve probably come up against a problem with file fields not behaving themselves when you add them to Features. This problem is particularly bad with taxonomy terms that have an image field, which are commonly put into Features as part of the site structure rather than client-entered data.

GUFF (Generic UUID file fields) solves this problem by providing an automated system to encode managed files (eg, file fields) into .php include files that are handled through the standard Features system, and can be put into version control.

GUFF works with UUID files, and once enabled it should Just Work. Has saved us a lot of pain.

Changing pager on Drupal 7

 Drupal  6 Responses »
Feb 142013
 

Sometimes you don’t want all those numbers on your pager. Or you don’t want the text ‘next’ etc. It is very easy to change those in a preprocess. This code changes the number of pages shown in the pager from the default down to 5, and changes the first, next, previous, last text to arrows.

function yourtheme_preprocess_pager(&$variables, $hook) {
  if ($variables['quantity'] > 5) $variables['quantity'] = 5;
  $variables['tags'][0] = '<<';
  $variables['tags'][1] = '<';
  $variables['tags'][3] = '>';
  $variables['tags'][4] = '>>';
}

Add this to your theme’s template.php and replace ‘yourtheme’ with your theme’s name.

Removing javascript from Drupal 7

 Drupal  No Responses »
Jan 222013
 

Every now and again, someone in IRC wants to know how to completely remove javascript from Drupal 7. This isn’t necessarily a good idea – there’s a lot of little things in Drupal that use javascript, and you really don’t want to remove javascript from the admin side of the site as it won’t be anywhere as easy to use. However if you are quite sure that you really, really do want to remove javascript, you need the following code in your theme’s template.php.

function yourtheme_js_alter(&$javascript) {
    $javascript = array();
}
function yourtheme_html_tag($variables){
    $element = $variables['element'];
    if ($element['#tag'] == 'script') return "";
    return theme_html_tag($variables);
}

Make sure you change “yourtheme” to the name of your theme. Clear cache, and you’ll have no javascript. Note that this completely removes *all* javascript including the default jquery from all pages, and if you want to remove it only from select pages you’ll need to wrap the code in conditionals.

MySQL Dramas

 Drupal, MySQL  1 Response »
Jul 012011
 

I was unhappy with the performance of our Drupal websites when using them logged in. We have a local test machine that is LAMP (Linux, Apahce, MySQL, PHP) and it was had page load times of over a second quicker than the production server that is WIMP (Windows, IIS, MySQL, PHP). While the machine are using different OS and Webservers that didn’t account for the issues. Using the Devel module it was telling me the MySQL queries were almost identical between the two machines but the page execution time was significantly slower on the production machine.

After using a profiling extension for PHP I tracked down the problem. PDO was taking over a second (!) to connect to the MySQL database on localhost. After much searching around it turns out the problem seems to be due to MySQL having issues with resolving names with IPv6 addresses. Windows Server 2008 R2 by default returns an IPv6 (::1) and IPv4 (127.0.0.1) address for localhost. In order to work around the issue I needed to add ‘127.0.0.1 localhost’ to the servers \Windows\System32\etc\hosts file. It should be noted for anyone else doing the same, make sure there is no IPv6 address for localhost in the hosts file either.

After making the change, database connections were instant and the performance of the sites improved considerably.

Age gate for Drupal 7

 Drupal, Programming  6 Responses »
May 232011
 

After not being able to find a module that worked quite as we wanted, I created a simple Age Gate module for Drupal 7. This module very basic and has various hardcoded paths in it.

The module redirects all anonymous users to the agegate page and requires that they check the ‘Over 18’ checkbox before they can view content on the site. If they don’t check to box and press submit they get redirected to a page at the path ‘access-denied’ (this is the page we use on our site). The module is coded to allow non agegate access to logged in users, the ‘user/login’ page and the ‘access-denied’ page.

Download it here. Module is provided as is. Agegate Module for Drupal 7