jyapayne/swig
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Clarify the text about remaining PHP constant oddity.

Browse source 
git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk@12752 626c5289-ae23-0410-ae9c-e8d60b6d4f22
This commit is contained in:
Olly Betts 2011-06-25 12:48:08 +00:00
commit 7d584f5204
1 changed files with 15 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

25
Doc/Manual/Php.html
View file

@ -180,9 +180,8 @@ other symbols unless care is taken to <tt>%rename</tt> them.
<H3><a name="Php_nn2_1"></a>31.2.1 Constants</H3>
<p>
These work in much the same way as in C/C++, constants can be defined
These work in much the same way as in C/C++. Constants can be defined
by using either the normal C pre-processor declarations, or the
<tt>%constant</tt> SWIG directive. These will then be available from
your PHP script as a PHP constant, (i.e. no dollar sign is needed to
@ -199,7 +198,7 @@ access them.) For example, with a swig interface file like this,
</div>
<p>
you can access the constants in your php script like this,
you can access the constants in your PHP script like this,
</p>
<div class="code"><pre>
@ -213,9 +212,16 @@ echo "E = " . E . "\n";
</div>
<p>
There are two peculiarities with using constants in PHP. The first is that
if you try to use an undeclared constant, it will evaluate to a string
set to the constant's name. For example,
There's one peculiarity of how constants work in PHP which it is useful
to note (this is not specific to SWIG though) - if you try to use an undeclared
constant, PHP will issue a warning and then expand the constant to a string
version of the constant's name. The warning will often be missed though as
if you're using PHP in a webserver, it will probably end up in error.log or
similar.
</p>
<p>
For example,
</p>
<div class="code"><pre>
@ -243,10 +249,9 @@ if(EASY_TO_MISPEL) {
</div>
<p>
will issue a warning about the undeclared constant, but will then
evaluate it and turn it into a string ('EASY_TO_MISPEL'), which
evaluates to true, rather than the value of the constant which would
be false. This is a feature!
The mis-spelled constant will become the string 'EASY_TO_MISPEL', which
is treated as true by the if test, when the value of the intended constant
would be treated as false!
</p>
<H3><a name="Php_nn2_2"></a>31.2.2 Global Variables</H3>