POSDIFF()
 Finds the first position from which two strings differ
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 Syntax

     POSDIFF(<cString1>,<cString2>,[<nIgnore>])
        --> nPosition

 Arguments

     <cString1> and <cString2>  Designate the two character strings
     that are compared.

     <nIgnore>  Designates how many characters at the beginning of the
     character strings are excluded from the search.  The default value
     excludes none (0).

 Returns

     POSDIFF() returns the first position where <cString1> and <cString2>
     differ.  If both character strings are equal, then the function returns
     0.

 Description

     POSDIFF() compares two strings and determines from which position the
     first difference occurs.  The <nIgnore> parameter allows you to exclude
     a particular number of characters from the beginning of both character
     strings from the search.

 Note

     .  Character strings of different lengths can be compared with
        each other (see examples).

 Examples

     .  This example compares two strings of the same length:

        cString1  :=  "X23AB$/A"
        cString2  :=  "X23A8$/A"
        ? POSDIFF(cString1, cString2)           // Result: 5

     .  Two strings of different lengths can also be compared:

        ? POSDIFF("AB", "ABC")                  // Result: 3