#32690 [NEW]: Using function_exists() doesn't always work.

From: gregt at maths dot otago dot ac dot nz Operating system: Linux PHP version: 4.3.9 PHP Bug Type: GD related Bug description: Using function_exists() doesn't always work. Description: ------------ When using function function_exists() to test for presence of a function, the result is sometimes wrong. Consider the following: echo "a:", function_exists(imagecreate),"<br>"; echo "b:", function_exists(imagecreatetruecolor),"<br>"; echo "c:", function_exists(imagecreatetruecolorrrr),"<br>"; echo phpinfo(8); This produces the output: a: 1 b: 1 c: <snip> gd GD Support enabled GD Version 1.6.2 or higher FreeType Support enabled FreeType Linkage with freetype JPG Support enabled PNG Support enabled WBMP Support enabled When I call imagecreatetruecolor(), I get: Warning: imagecreatetruecolor(): requires GD 2.0 or later in /home/gregt/public_html/gd/gdtest.php on line 8 Obviously I don't have a proper implementation of the imagecreatetruecolor function, but there is still code there to throw an error, so function_exists blindly assumes the function is present. Reproduce code: --------------- <? echo "a:", function_exists(imagecreate),"<br>"; echo "b:", function_exists(imagecreatetruecolor),"<br>"; echo "c:", function_exists(imagecreatetruecolorrrr),"<br>"; echo phpinfo(8); ?> Expected result: ---------------- a: 1 b: c: Actual result: -------------- a: 1 b: 1 c: -- Edit bug report at http://bugs.php.net/?id=32690&edit=1 -- Try a CVS snapshot (php4): http://bugs.php.net/fix.php?id=32690&r=trysnapshot4 Try a CVS snapshot (php5.0): http://bugs.php.net/fix.php?id=32690&r=trysnapshot50 Try a CVS snapshot (php5.1): http://bugs.php.net/fix.php?id=32690&r=trysnapshot51 Fixed in CVS: http://bugs.php.net/fix.php?id=32690&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=32690&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=32690&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=32690&r=needscript Try newer version: http://bugs.php.net/fix.php?id=32690&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=32690&r=support Expected behavior: http://bugs.php.net/fix.php?id=32690&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=32690&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=32690&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=32690&r=globals PHP 3 support discontinued: http://bugs.php.net/fix.php?id=32690&r=php3 Daylight Savings: http://bugs.php.net/fix.php?id=32690&r=dst IIS Stability: http://bugs.php.net/fix.php?id=32690&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=32690&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=32690&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=32690&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=32690&r=mysqlcfg