_EdUndoOn( ) API Library Routine Example
The following example shows how to use _EdUndoOn( ) to group edit operations that you can undo as a group using _EdUndo( ).
SET LIBRARY TO EDUNDOON
= EDUNDOON("x") && edit file "x"
#include <pro_ext.h>
#define TRUE 1
#define FALSE 0
FAR Example(ParamBlk FAR *parm)
{
char FAR *pFileName;
WHANDLE wh;
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);
pFileName = (char FAR *) _HandToPtr(parm->p[0].val.ev_handle);
pFileName[parm->p[0].val.ev_length] = '\0';
wh = _EdOpenFile(pFileName, FO_READWRITE);
_HUnLock(parm->p[0].val.ev_handle);
_EdUndoOn(wh, TRUE); // start undo group
_EdSetPos(wh, _EdGetLinePos(wh, 13));
_EdInsert(wh, "Hello, world\n", _StrLen("Hello, world\n"));
_EdSelect(wh, _EdGetLinePos(wh, 14), _EdGetLinePos(wh, 16));
_EdIndent(wh, 1);
_EdUndoOn(wh, FALSE); // end undo group
_EdUndoOn(wh, TRUE); // start another undo group
_EdSelect(wh, _EdGetLinePos(wh, 9), _EdGetLinePos(wh, 12));
_EdDelete(wh);
_EdSetPos(wh, _EdGetLinePos(wh, 13));
_EdInsert(wh, "Hello, world\n", _StrLen("Hello, world\n"));
_Execute("WAIT WINDOW 'Press any key to undo changes.'");
_EdUndoOn(wh, TRUE); // undoes to start of undo group
}
FoxInfo myFoxInfo[] = {
{"EDUNDOON", (FPFI) Example, 1, "C"},
};
FoxTable _FoxTable = {
(FoxTable FAR *) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo
};