c-treeDB API API for C

ctdbNumberOfKeyEntries

Declaration

LONG ctdbDECL ctdbNumberOfKeyEntries(CTHANDLE Handle, NINT index);

Description

ctdbNumberOfKeyEntries() retrieves the number key entries in an index file identified by its index number.

Handle is a table handle or a handle that can be evaluated into a table handle.
index identifies the index to obtain the number of entries. The first index number is zero.

Return Values

ctdbNumberOfKeyEntries() returns the number of key entries in the index. ctdbNumberOfKeyEntries() returns -1 and users should call the ctdbGetError() function to retrieve the error code.

See c-tree Plus Error Codes for a complete listing of valid c-tree Plus error values.

Example

LONG Estimate(CTHANDLE Handle, NINT index)

{

LONG Retval = 0;

TEXT key1[16], key2[16];

VRLEN klen;

/* set the default index */

ctdbSetDefaultIndex(Handle, index);

/* load the first record */

ctdbFirstRecord(Handle);

/* build the target key for the first record */

klen = sizeof(key1);

ctdbBuildTargetKey(Handle, CTFIND_EQ, key1, &klen);

/* load the last record */

ctdbLastRecord(Handle);

/* build the target key for the last record */

klen = sizeof(key2);

ctdbBuildTargetKey(Handle, CTFIND_EQ, key2, &klen);

/* get the estimated span */

Retval = ctdbEstimateSpan(Handle, key1, key2);

if (Retval > 0)

Retval--;

return Retval;

}