Data Type Conversion

A C variable declaration must be compatible with the Ingres value it represents. Numeric Ingres values can be set by and retrieved into numeric variables, and Ingres character values can be set by and retrieved into character variables.

Data type conversion occurs automatically for different numeric types such as from floating-point database column values into integer C variables, and for character strings, such as from varying-length Ingres character fields into fixed-length C character string buffers.

Ingres does not automatically convert between numeric and character types. You must use the Ingres type conversion operators, the Ingres ascii function, or a C conversion routine for this purpose.

Ingres Type	C Type
char(N)	char [N+1]
varchar(N)	char [N+1]
char(N)(with embedded nulls)	varchar
varchar(N)(with embedded nulls)	varchar
integer1	short
integer2	short
smallint	short
integer	int
integer	long
float4	float
bigint	long (64-bit); long long (32-bit)
float	double
date or ingresdate	char [26]
ansidate	char [11]
time without time zone	char [22]
time with time zone	char [32]
time with local time zone	char [32]
timestamp without time zone	char [40]
timestamp with time zone	char [50]
timestamp with local time zone	char [50]
interval year to month	char [16]
interval day to second	char [46]
money	double
table_key	char[8 ]
object_key	char[16]
decimal	double
long varchar	char[ ]
long varchar (with embedded nulls)	char[ ]
byte	char[ ]
varbyte	char[ ]
long byte	char[ ]
nchar(N)	wchar_t[N+1]
nvarchar(N)	wchar_t[N+1]
long nvarchar (with embedded nulls)	nvarchar