pub unsafe trait CData {
// Required methods
fn cdata_type(&self) -> CDataType;
fn indicator_ptr(&self) -> *const isize;
fn value_ptr(&self) -> *const c_void;
fn buffer_length(&self) -> isize;
}Expand description
Provides description of C type layout and pointers to it. Used to bind and buffers to ODBC statements.
Safety
In case of variable sized types Self::indicator_ptr must not exceed the value pointed to by
Self::value_ptr. This requirement is a bit tricky since, if the same indicator buffer is
used in an output paramater the indicator value may be larger in case of truncation.
Required Methods§
sourcefn cdata_type(&self) -> CDataType
fn cdata_type(&self) -> CDataType
The identifier of the C data type of the value buffer. When it is retrieving data from the
data source with fetch, the driver converts the data to this type. When it sends data to
the source, the driver converts the data from this type.
sourcefn indicator_ptr(&self) -> *const isize
fn indicator_ptr(&self) -> *const isize
Indicates the length of variable sized types. May be zero for fixed sized types. Used to determine the size or existence of input parameters.
sourcefn value_ptr(&self) -> *const c_void
fn value_ptr(&self) -> *const c_void
Pointer to a value corresponding to the one described by cdata_type.
sourcefn buffer_length(&self) -> isize
fn buffer_length(&self) -> isize
Maximum length of the type in bytes (not characters). It is required to index values in
bound buffers, if more than one parameter is bound. Can be set to zero for types not bound
as parameter arrays, i.e. CStr.