可変長式の最大長を入手するために使用する %LEN

%LEN の 2 番目のパラメーターが *MAX である場合、この関数は、可変長式の最大文字数を戻します。 %LEN の最初のパラメーターがフィールド名であれば、この値は、フィールドの定義長と同じになります。例えば、可変長 UCS-2 フィールドが 25C と定義されている場合、%LEN(fld:*MAX) は 25 を戻します。

図 1. *MAX を指定した %LEN の例

D char_varying    s            100a   varying
D ucs2_varying    s           5000c   varying
D graph_varying   s           7000g   varying(4)
D graph_fld10     s             10g
D char_fld10      s             10a
 /free
     // Calculate several length and size values
     // - The maximum length, %LEN(*MAX), measured in characters
     // - The current length, %LEN, measured in characters
     // - The size, %SIZE, measured in bytes, including the
     //   2- or 4-byte length prefix

     // Each alphanumeric character has one byte     char_varying = 'abc';
     // Length is 3     max_len = %len(char_varying : *MAX);
     len = %len(char_varying);
     size = %size(char_varying);
     // max_len = 100
     // len     = 3
     // size    = 102    (100 + 2)

     // Each UCS-2 character has two bytes     ucs2_varying = 'abc';
     // Length is 3     max_len = %len(ucs2_varying : *MAX);
     len = %len(ucs2_varying);
     size = %size(ucs2_varying);
     // max_len = 5000
     // len     = 3
     // size    = 10002    (5000 * 2 + 2)

     // Each graphic character has two bytes.
     // For field graph_varying, VARYING(4) was specified,
     // so the length prefix has four bytes     graph_varying = graph_fld10;
     // Length is 10     max_len = %len(graph_varying : *MAX);
     len = %len(graph_varying);
     size = %size(graph_varying);
     // max_len = 7000
     // len     = 10
     // size    = 14004    (7000 * 2 + 4)

     // Calculate %LEN(*MAX) of a concatenation     graph_varying = %subst(graph_fld10:1:5);
     // Length is 5     max_len = %len(graph_varying + graph_fld10 : *MAX);
     len = %len(graph_varying + graph_fld10);
     // max_len = 7010 (7000 + 10)
     // len     = 15   (5 + 10)

     // Calculate %LEN(*MAX) of a %TRIM expression     char_fld10 = '1234';
     // Trimmed length is 4     max_len = %len(%trim(char_fld10) : *MAX);
     len = %len(%trim(char_fld10));
     // max_len = 10 (maximum trimmed length)
     // len = 4      (actual trimmed length)