PHP extension version inconsistencies; a more reliable way?

Question

Having run the following:

foreach(get_loaded_extensions() as $name){
    $extensions[strtolower($name)] = phpversion($name);
}
var_dump($extensions);

I notice that some of the loaded extensions don't show a version, having false instead, for instance:

'pcre' => boolean false

However, when I hit up phpinfo(), it shows a version number:

Why isn't the phpversion() function fetching the correct results? I understand in this instance I could simply pull PCRE_VERSION, but needing to do so for some but not all extensions is silly; gd shows false too.

---

Edit: Fix;

foreach(get_loaded_extensions() as $name){
    $extensions[strtolower($name)] = phpversion($name);
}
$extensions = array_replace($extensions, array(
    'iconv' => ICONV_VERSION,
    'pcre' => PCRE_VERSION,
    'libxml' => LIBXML_DOTTED_VERSION,
    'gd' => GD_VERSION,
    // others i may be missing, will get to it
));

---

Edit: Here's the full dump and the phpinfo() output, just for giggles:

array
  'core' => string '5.3.8' (length=5)
  'bcmath' => boolean false
  'calendar' => boolean false
  'com_dotnet' => string '0.1' (length=3)
  'ctype' => boolean false
  'date' => string '5.3.8' (length=5)
  'ereg' => boolean false
  'filter' => string '0.11.0' (length=6)
  'ftp' => boolean false
  'hash' => string '1.0' (length=3)
  'iconv' => boolean false
  'json' => string '1.2.1' (length=5)
  'mcrypt' => boolean false
  'spl' => string '0.2' (length=3)
  'odbc' => string '1.0' (length=3)
  'pcre' => boolean false
  'reflection' => string '$Revision: 313665 $' (length=19)
  'session' => boolean false
  'standard' => string '5.3.8' (length=5)
  'mysqlnd' => string 'mysqlnd 5.0.8-dev - 20102224 - $Revision: 310735 $' (length=50)
  'tokenizer' => string '0.1' (length=3)
  'zip' => string '1.9.1' (length=5)
  'zlib' => string '1.1' (length=3)
  'libxml' => boolean false
  'dom' => string '20031129' (length=8)
  'pdo' => string '1.0.4dev' (length=8)
  'bz2' => boolean false
  'simplexml' => string '0.1' (length=3)
  'wddx' => boolean false
  'xml' => boolean false
  'xmlreader' => string '0.1' (length=3)
  'xmlwriter' => string '0.1' (length=3)
  'apache2handler' => boolean false
  'phar' => string '2.0.1' (length=5)
  'mbstring' => boolean false
  'exif' => string '1.4 $Id: exif.c 314376 2011-08-06 14:47:44Z felipe $' (length=52)
  'gd' => boolean false
  'gettext' => boolean false
  'imap' => boolean false
  'mysql' => string '1.0' (length=3)
  'mysqli' => string '0.1' (length=3)
  'pdo_mysql' => string '1.0.2' (length=5)
  'pdo_odbc' => string '1.0.1' (length=5)
  'pdo_sqlite' => string '1.0.1' (length=5)
  'soap' => boolean false
  'sockets' => boolean false
  'sqlite' => string '2.0-dev' (length=7)
  'sqlite3' => string '0.7-dev' (length=7)
  'tidy' => string '2.0' (length=3)
  'xmlrpc' => string '0.51' (length=4)
  'mhash' => boolean false
  'xdebug' => string '2.1.1' (length=5)

Answer 1

phpversion() returns the version of that extension, or FALSE if there is no version information associated or the extension isn't enabled.

What you saw in phpinfo() is not the version information of the extension but the c-client version of the library. The prce extension itself has no version information.