Metadata

const C8Char *C8GetFunctionName(C8Udf *ctx) – Purpose: Returns the name of a function as defined in the UDF XML file.

Parameters:

ctx: A context object that contains information about the parameters passed to the UDF.

Returns: The name of a function as defined in the UDF XML file. The return value is a pointer. Do not change the memory that the pointer points to or C8Free() this pointer.

const C8Char *C8GetLibraryName(C8Udf *ctx) – Purpose: Returns the name of the library as defined in the UDF XML file.

Parameters:

ctx: A context object that contains information about the parameters passed to the UDF.

Returns: The name of the library as defined in the UDF XML file. The return value is a pointer. Do not change the memory that the pointer points to, or C8Free() this pointer.

const C8UInt C8GetNumberInputParameters(C8Udf *ctx) – Purpose: Given a context, ctx, return the number of input parameters. This may be used for loops to fill arrays, error checking, and so on.

Parameters:

ctx: A context object that contains information about the parameters passed to the UDF.

Returns: The number of input parameters stored in the context object.

const C8Char *C8GetInputType(C8Udf *ctx, C8UInt ndx) – Purpose: Provides the type string for that parameter as provided in the Parameter attribute in the UDF XML file. This may be used in error messages or type checking.

Parameters:

ctx: A context object that contains information about the parameters passed to the UDF.
ndx: Indicates which parameter in the context object to get the type string for. The first parameter is 0.

Returns: The type string for the parameter as provided in the Parameter attribute in the UDF XML file. The return value is a pointer. Do not change the memory that the pointer points to, or C8Free() this pointer.

const C8_TYPES C8GetInputEnumType(C8Udf *ctx, C8UInt ndx) – Purpose: Provides the type enumeration for that parameter. This may be used in error messages or type checking. For definitions of the valid values of the enumeration, see the definition of _C8_TYPES in the file c8types.h.

Parameters:

ctx: A context object that contains information about the parameters passed to the UDF.
ndx: Indicates which parameter in the context object to get the type string for.

Returns: The type string for the specified parameter as provided in the Parameter attribute in the UDF XML file.

const C8Char *C8GetInputName(C8Udf *ctx, C8UInt ndx) – Purpose: Provides the name of the parameter. This may be used in error messages or type checking.

Parameters:

ctx: A context object that contains information about the parameters passed to the UDF.
ndx: Indicates which parameter in the context object to get the type string for.

Returns: The name of the parameter as provided in the Parameter attribute in the UDF XML file. Do not change the memory that the pointer points to, or C8Free() this pointer.

const C8Char *C8GetOutputType(C8Udf *ctx) – Purpose: Provides the type enumeration for the output parameter. This may be used in error messages or type checking.

Parameters:

ctx: A context object that contains information about the parameters passed to the UDF.

Returns:The type string for the output parameter. The return value is a pointer. Do not change the memory that the pointer points to, or C8Free() this pointer.

const enum C8_TYPES C8GetOutputEnumType(C8Udf *ctx) – Purpose: Provides the type enumeration for that parameter. This may be used in error messages or type checking.

Parameters:

ctx: A context object that contains information about the parameters passed to the UDF.

Returns: The type enumeration for that parameter.

const C8Char *C8GetOutputName(C8Udf *ctx) – Purpose: Provides the string for an output parameter name. This may be used in error messages or type checking.

Parameters:

ctx: A context object that contains information about the parameters passed to the UDF.

Returns: The string for the output parameter name. If you have not provided an output name in the UDF XML, then this string will be empty. The return value is a pointer. Do not change the memory that the pointer points to, or C8Free() this pointer.

void C8SetSessionState(C8Udf *ctx, void *data) – Purpose: Stores the session state, which is a set of user-defined information that you want to make available across multiple invocations of the UDF's execute() function. Although the session state is retained by the , the user is responsible for populating and updating the session state. The session state does not contain a size because the session is not persisted over restarts. For this season, a session state should thus be created in a user-defined class allocated with the new operator or in a user-defined struct using C8Malloc() or a similar heap-based allocation. Session structures must not be defined on the stack because the stack is popped each time the function exits. When you are done with the session state, free it. For tips and warnings about allocating and de-allocating memory, see the section titled Notes about Allocating and Deallocating Memory in In-process Code.

In the shutdown() callback function, the session state should be destroyed. Storing and retrieving session information is optional.

Parameters:

ctx: A context object that contains information about the parameters passed to the UDF.
data: A pointer to the state information that you would like to be able to see the next time that the adapter's execute() function is called.

Returns: Nothing.

void * C8GetSessionState(C8Udf *ctx) – Purpose: Returns the session state information associated with an instance of a UDF. On the initial call to C8GetSessionState(), a null pointer is returned. This indicates no session exists, so you are responsible for creating a session. The session state is usually constructed by a call to C8Malloc() and populated with a user-defined structure. Using a static or global for session states is not thread safe and the consequences are undefined.

Parameters:

ctx: A context object that contains information about the parameters passed to the UDF.

Returns: A pointer to session state information. The exact structure of this information is defined by you, so the function simply returns a pointer to the memory without interpreting that memory in any way.