FairCom ISAM for C

Field Types

c-tree recognizes the following field types:

Signed and unsigned char’s.
Signed and unsigned 2-byte/4-byte integers.
Single, double and extended precision floats.
Scaled BCD numbers.
Arbitrary fixed-length data.
Fixed- and variable-length strings delimited by a specified field delimiter.
Fixed- and variable-length strings whose actual contents are specified by 1-byte, 2-byte or 4-byte length counts which occur at the beginning of the field.

The field delimiter defaults to a null byte. However, the SetVariableBytes() function can be used to change the delimiter to a value other than the default.

Following the Pascal string storage convention, the value stored in the length count byte(s) corresponds to the length of the string and does not include the length count bytes themselves. However, the length count byte(s) should be included in the length specified in the DODA flen element. For example, a 10-byte string of type CT_F4STRING has a length of 14-bytes in the flen element of the DODA, however, the length stored in the byte count portion of the data record would be 10.

Caution: When using the CT_F2STRING and CT_F4STRING types, the byte count can be affected by the alignment of the compiler.

A fixed-length field with varying length contents means that the field occupies a fixed number of bytes in the record structure, but that a field delimiter or a length count specifies the actual amount of data in the field.

The constants used to represent these field types (found in ctport.h) are:

Symbolic Constant	Interpretation
CT_BOOL	1-byte Boolean.
CT_CHAR	Signed char.
CT_CHARU	Unsigned char.
CT_INT2	Signed 2-byte integer.
CT_INT2U	Unsigned 2-byte integer.
CT_INT4	Signed 4-byte integer.
CT_INT4U	Unsigned 4-byte integer.
CT_INT8	Signed 8-byte integer.
CT_INT8U	Unsigned 8-byte integer.
CT_MONEY	Signed 4-byte integer interpreted as number of pennies up to a precision of 9.
CT_DATE	Unsigned 4-byte integer interpreted as date.
CT_TIME	Unsigned 4-byte integer interpreted as time.
CT_SFLOAT	4-byte floating point.
CT_DFLOAT	8-byte floating point.
CT_EFLOAT	Extended precision floating point (not supported as a key segment).
CT_TIMES	8-byte floating point.
CT_ARRAY	Arbitrary fixed length data.
CT_RESRVD	Reserved for future use.
CT_FSTRING	Fixed length field delimited data.
CT_FPSTRING	Fixed length data with 1-byte length count.
CT_F2STRING	Fixed length data with 2-byte length count.
CT_F4STRING	Fixed length data with 4-byte length count.
CT_STRING	Varying length field delimited data. (NUL terminated.)
CT_PSTRING	Varying length data with 1-byte length count.
CT_2STRING	Varying length data with 2-byte length count.
CT_4STRING	Varying length data with 4-byte length count.
CT_UNICODE	A variable-length field containing a UTF16 encoded, null terminated string.
CT_2UNICODE	A variable-length field that begins with a 2-byte integer specifying the number of bytes in the following UTF16 encoded string.
CT_FUNICODE	A fixed length field containing a UTF16 encoded, null terminated string.
CT_F2UNICODE	A fixed length field that begins with a 2-byte integer specifying the number of bytes in the following UTF16 encoded string.
CT_UNIXTIME_T	A 4 byte UNIX timestamp that maps to the SQL TIMESTAMP type
CT_UNIXTIME64_T	An 8 byte UNIX timestamp that maps to the SQL TIMESTAMP type