ASC function

Converts a character expression representing a single character into the corresponding ASCII (or internal code page) value, returned as an INTEGER.

Syntax 

 

ASC ( expression [ , target-codepage [ , source-codepage ] ] )

expression

An expression with a value of a single character that you want to convert to an ASCII (or internal code page) integer value. If expression is a constant, you must enclose it in quotation marks (" "). If the value of expression is other than a single character, ASC returns the value -1.

The values for expression are case sensitive. For example, ASC("a") returns a different value than ASC("A").

target-codepage

A character-string expression that evaluates to the name of a code page. The name that you specify must be a valid code page name available in the OpenEdge-install-dir/convmap.cp file (a binary file that contains all of the tables that ABL uses for character management). If you supply a non-valid name, the ASC function returns the value -1 and returns a runtime error. Before returning an integer value, the ASC function converts expression from source-codepage to target-codepage. The returned integer value is relative to target-codepage. If you do not specify target-codepage, the value returned is the code page identified with the Internal Code Page (-cpinternal) parameter.

source-codepage

A character-string expression that evaluates to the name of a code page. The name that you specify must be a valid code page name available in the OpenEdge-install-dir/convmap.cp file. If you supply a non-valid name, the ASC function returns the value -1. The source-codepage specifies the name of the code page to which expression is relative. The default value of source-codepage is the code page identified with the Internal Code Page (-cpinternal) parameter.

Example 

The following procedure counts how many customers names begin with each of the letters, A-Z. It counts all other customers separately. The procedure uses the ASC function to translate a letter into an integer that it uses as an array subscript for counting.

 

r-asc.p

DEFINE VARIABLE ix   AS INTEGER NO-UNDO. DEFINE VARIABLE jx   AS INTEGER NO-UNDO. DEFINE VARIABLE ltrl AS INTEGER NO-UNDO EXTENT 27.   FOR EACH Customer NO-LOCK:   ix = ASC(SUBSTRING(Customer.Name,1,1)).   IF ix < ASC("A") or ix > ASC("Z") THEN ix = EXTENT(ltrl).   ELSE ix = ix - ASC("A") + 1.   ltrl[ix] = ltrl[ix] + 1. END.   DO jx = 1 TO EXTENT(ltrl) WITH NO-LABELS USE-TEXT:   IF jx <= 26 THEN     DISPLAY CHR(ASC("A") + jx - 1) @ ltr-name AS CHARACTER FORMAT "x(5)".   ELSE     DISPLAY "Other" @ ltr-name.   DISPLAY ltrl[jx]. END.

Notes 

The ASC function returns the corresponding value in the specified character set. By default, the value of SESSION:CHARSET is iso8859-1. You can set a different internal code page by specifying the Internal Code Page (-cpinternal) parameter. For more information, see OpenEdge Development: Internationalizing Applications.

The ASC function is both double-byte and Unicode enabled. If the expression argument yields a double-byte character or multi-byte Unicode character in the target code page, this function can return a value greater than 255.

See also 

CHR function, CODEPAGE-CONVERT function, INTEGER function, SESSION system handle