php man page for variant_sub

VARIANT_SUB(3)								 1							    VARIANT_SUB(3)

variant_sub - Subtracts the value of the right variant from the left variant value

SYNOPSIS
       mixed variant_sub (mixed  $left, mixed  $right)

DESCRIPTION
	Subtracts $right from $left.

PARAMETERS
	      o $left
		- The left operand.

	      o $right
		- The right operand.

       Note

	       As  with  all  the variant arithmetic functions, the parameters for this function can be either a PHP native type (integer, string,
	      floating point, boolean or NULL), or an instance of a COM, VARIANT or DOTNET class. PHP native types will be converted  to  variants
	      using  the  same	rules  as  found  in  the constructor for the "VARIANT" class. COM and DOTNET objects will have the value of their
	      default property taken and used as the variant value.

	       The variant arithmetic functions are wrappers around the similarly named functions in the COM  library;	for  more  information	on
	      these  functions, consult the MSDN library. The PHP functions are named slightly differently; for example variant_add(3) in PHP cor-
	      responds to VarAdd()  in the MSDN documentation.

RETURN VALUES
       Variant Subtraction Rules

       +--------------------------------------------------+--------------------------+
       |		       If			  |			     |
       |						  |			     |
       |						  |	      Then	     |
       |						  |			     |
       +--------------------------------------------------+--------------------------+
       |     Both expressions are of the string type	  |			     |
       |						  |			     |
       |						  |	  Subtraction	     |
       |						  |			     |
       |One expression is a string type and the  other	a |			     |
       |character					  |			     |
       |						  |			     |
       |						  |	  Subtraction	     |
       |						  |			     |
       |One  expression  is  numeric  and  the other is a |			     |
       |string						  |			     |
       |						  |			     |
       |						  |	  Subtraction.	     |
       |						  |			     |
       |	  Both expressions are numeric		  |			     |
       |						  |			     |
       |						  |	  Subtraction	     |
       |						  |			     |
       |	    Either expression is NULL		  |			     |
       |						  |			     |
       |						  |	NULL is returned     |
       |						  |			     |
       |	   Both expressions are empty		  |			     |
       |						  |			     |
       |						  | Empty string is returned |
       |						  |			     |
       +--------------------------------------------------+--------------------------+
SEE ALSO
       variant_add(3).

PHP Documentation Group 													    VARIANT_SUB(3)