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Returns the file channel of the memo file associated with the specified workarea.
FCHAN _MemoChan(int workarea) int workarea; /* Work area number. */ |
Remarks
If no database is open in that work area or the database has no memo file, _MemoChan( ) returns – 1.
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 retrieves the contents of a memo field. _MemoChan( – 1) returns a file channel to the memo file for the current work area. This FCHAN is used as an argument to the low-level file I/O API callbacks.
Visual FoxPro Code
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SET LIBRARY TO MEMOCHAN CREATE TABLE WMemo (MemoField M) APPEND BLANK REPLACE MemoField WITH "Hello, World." ? GETMEMO(@MemoField) | |
C Code
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#include <pro_ext.h>
FAR FindMemoEx(ParamBlk FAR *parm)
{
Locator FAR *memoFldLoc;
FCHAN fchMemo;
char FAR *memoContents;
int memoLen;
long loc;
if ((fchMemo = _MemoChan(-1)) == -1)
{
_UserError("_MemoChan() failed");
}
memoFldLoc = &parm->p[0].loc;
if ((loc = _FindMemo(memoFldLoc)) < 0)
{
_UserError("_FindMemo() failed");
}
if ((memoLen = _MemoSize(memoFldLoc)) < 0)
{
_UserError("_MemoSize() failed");
}
if ((memoContents = _Alloca(memoLen + 1)) == 0)
{
_Error(182); // "Insufficient memory"
}
_FSeek(fchMemo, loc, FS_FROMBOF);
_FRead(fchMemo, memoContents, memoLen);
memoContents[memoLen] = '\0';
_RetChar(memoContents);
}
FoxInfo myFoxInfo[] = {
{"GETMEMO", (FPFI) FindMemoEx, 1, "R"},
};
FoxTable _FoxTable = {
(FoxTable FAR *) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo
}; | |