_NameTableIndex( ) API Library Routine
Returns the name table index that corresponds to a given name, or returns – 1 if that name isn't in the name table.
NTI _NameTableIndex(char FAR *name)
char FAR *name; /* Name. */
Remarks
The name may be found in the name table even though a variable with the name name doesn't exist. To determine whether a variable with the name name exists, use _FindVar( ), specifying the name table index returned by _NameTableIndex( ) as the nti parameter.
For more information on how to create an API library and integrate it with Visual FoxPro, see Accessing the Visual FoxPro API.
Example
The following example releases a memory variable whose name is given as a character argument. Note that _NameTableIndex( ) finds the variable name after it has been released. Therefore, _NameTableIndex( ) is used in combination with _FindVar( ) to make sure the memory variable is currently defined.
Visual FoxPro Code
SET LIBRARY TO NTI
x = 123
= XRELEASE("x")
C Code
#include <pro_ext.h>
FAR ReleaseEx(ParamBlk FAR *parm)
{
NTI nti;
char FAR *name;
int exitCode;
Locator loc;
// Null terminate character string, name of variable
if (!_SetHandSize(parm->p[0].val.ev_handle,
parm->p[0].val.ev_length+1))
{
_Error(182); // "Insufficient memory"
}
_HLock(parm->p[0].val.ev_handle);
name = (char FAR *) _HandToPtr(parm->p[0].val.ev_handle);
name[parm->p[0].val.ev_length] = '\0';
if ((nti = _NameTableIndex(name)) == -1)
{
_HUnLock(parm->p[0].val.ev_handle);
_UserError("Cannot find variable in name table.");
}
_HUnLock(parm->p[0].val.ev_handle);
if (_FindVar(nti, -1, &loc))
{
_PutStr("\nVariable exists prior to _Release().");
}
if ((exitCode =_Release(nti)) < 0)
{
_Error(-exitCode);
}
_HLock(parm->p[0].val.ev_handle);
name = (char FAR *) _HandToPtr(parm->p[0].val.ev_handle);
name[parm->p[0].val.ev_length] = '\0';
if ((nti = _NameTableIndex(name)) != -1)
{
_PutStr("\n_NameTableIndex() still finds variable \
after it is released.");
}
_HUnLock(parm->p[0].val.ev_handle);
if (!_FindVar(nti, -1, &loc))
{
_PutStr("\nVariable does not exist after _Release().");
}
}
FoxInfo myFoxInfo[] = {
{"XRELEASE", (FPFI) ReleaseEx, 1, "C"},
};
FoxTable _FoxTable = {
(FoxTable FAR *) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo
};
See Also
Concepts
Reference
_FindVar( ) API Library Routine
_NewVar( ) API Library Routine
_ObjectRelease( ) API Library Routine