DataBlade API Programmer's Manual Chapter 12: DataBlade API Function Descriptions

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#include "miloback.h"

...
const char *mi_large_object_filename(conn, LO_handle, spec)

		MI_CONNECTION *conn;

		MI_LOHANDLE *LO_handle;

		const char *spec; 


conn
is a pointer to the connection descriptor that a previous call to mi_open() or mi_server_connect() has established.

LO_handle
is a pointer to the handle for the smart large object being copied. An MI_LOHANDLE value is returned by any routine that creates a smart large object or in query results returned by mi_value().

spec
is a specification for the destination file pathname of the smart large object to be placed in a file. The specification can contain the wildcard character ? to help guarantee filename uniqueness. The wildcard characters are replaced with the hexadecimal object ID of the smart large object or as much of it as fits in the given number of wildcards. Wildcards are read from the end of the string backward. You can use a maximum of 16 question marks (?). Extra wildcard characters (more than 16) are left unaltered.


For example, a spec value of /tmp/pic?????.gif puts up to five characters of the object ID in the name. This value might result in the filename /tmp/pic203b2.gif, but a spec value of /tmp/pic??.gif would yield /tmp/picb2.gif for the same smart large object.
As another example, /tmp/pic???.??? becomes /tmp/pic020.362.


The specification can also have! as its last character, in which case no modification is performed on the filename, except to remove the  !. Use the special character! when you want a filename for a single smart large object and collision is not an issue.


If no special characters are found in the specification, a period and the object ID are appended to the filename. For example, /tmp/gifpic might yield /tmp/gifpic.00000000000203b2.


This file-naming strategy enables a server function to iterate across multiple row or column values, using a unique filename value for each.





 



Valid in Client Application?

Valid in Server Routine?

Yes
Yes