New Functions
  
   PHP 5.3 introduced some new functions:
  
  PHP Core:
  
  Date/Time:
  
  GMP:
  
  Hash:
  
  IMAP:
  
   - 
    
     imap_gc()
     - Clears IMAP cache.
    
   
- 
    
     imap_utf8_to_mutf7()
     - Encode a UTF-8 string to modified UTF-7.
    
   
- 
    
     imap_mutf7_to_utf8()
     - Decode a modified UTF-7 string to UTF-8.
    
   
JSON:
  
  MySQL Improved:
  
  OpenSSL:
  
  PCNTL:
  
  PCRE:
  
   - 
    
     preg_filter()
     - Perform a regular expression search and replace, returning only results
     which matched the pattern.
    
   
Semaphore:
  
  
   The following functions are now natively implemented, making them available
   on all operating systems which can run PHP: