_DBSkip( ) API Library Routine

Visual FoxPro 9.0 SP2

_DBSkip( ) API Library Routine


long _DBSkip(int workarea, long distance) int workarea; /* Work area. / long distance; / Number of records to skip. */

Remarks

_DBSkip( ) respects the active index and filter expressions, just like the Visual FoxPro SKIP command. The distance may be positive or negative. _DBSkip( ) returns the record number of the new record.

Use _DBStatus( ) to check for end of file and beginning of file conditions. If you try to skip forward from the end of the file, or skip backwards from the beginning of the file, _DBSkip( ) returns a negative integer whose absolute value is a Visual FoxPro error number.

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 works like the Visual FoxPro SKIP command.

Visual FoxPro Code

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SET LIBRARY TO DBSKIP ON ERROR DO expectError DO CreateTest USE = DBSKIP(1) && _Error() called: no DBF in use USE test GO TOP = DBSKIP(-1) = DBSKIP(-1) && _Error() called: at top of file GO BOTT = DBSKIP(1) = DBSKIP(1) && _Error() called: at bottom of file ON ERROR PROCEDURE expectError ? "ERROR: " + MESSAGE() RETURN PROCEDURE CreateTest CREATE TABLE test (ABC C(20)) APPEND BLANK REPLACE ABC WITH "This is record 1" APPEND BLANK REPLACE ABC WITH "This is record 2" APPEND BLANK REPLACE ABC WITH "This is record 3" APPEND BLANK REPLACE ABC WITH "This is record 4" GO TOP RETURN

Copy Code

SET LIBRARY TO DBSKIP  
ON ERROR DO expectError
DO CreateTest
USE
= DBSKIP(1)       && _Error() called: no DBF in use
USE test
GO TOP
= DBSKIP(-1)
= DBSKIP(-1)      && _Error() called: at top of file
GO BOTT
= DBSKIP(1)
= DBSKIP(1)      && _Error() called: at bottom of file
ON ERROR
PROCEDURE expectError
   ? "ERROR: " + MESSAGE()
RETURN
PROCEDURE CreateTest
   CREATE TABLE test (ABC C(20))
   APPEND BLANK
   REPLACE ABC WITH "This is record 1"
   APPEND BLANK
   REPLACE ABC WITH "This is record 2"
   APPEND BLANK
   REPLACE ABC WITH "This is record 3"
   APPEND BLANK
   REPLACE ABC WITH "This is record 4"
   GO TOP
RETURN

C Code

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#include <pro_ext.h> FAR Example(ParamBlk FAR pblk) { int RetCode; if ((RetCode = _DBSkip(-1, pblk->p[0].val.ev_long)) < 0) { _PutStr("\nError encountered in example program."); _Error(-RetCode); // _DBSkip() returns negative error code } _RetInt(RetCode, 10); } FoxInfo myFoxInfo[] = { {"DBSKIP", (FPFI) Example, 1, "I"}, }; FoxTable _FoxTable = { (FoxTable FAR ) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo };

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#include <pro_ext.h>
FAR Example(ParamBlk FAR *pblk)
{
   int RetCode;
   if ((RetCode = _DBSkip(-1, pblk->p[0].val.ev_long)) < 0) {
      _PutStr("\nError encountered in example program.");
      _Error(-RetCode);  // _DBSkip() returns negative error code
   }
   _RetInt(RetCode, 10);
}
FoxInfo myFoxInfo[] = {
   {"DBSKIP", (FPFI) Example, 1, "I"},
};
FoxTable _FoxTable = {
   (FoxTable FAR *) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo
};

_DBSkip( ) API Library Routine

Remarks

Example

Visual FoxPro Code

C Code

See Also

Reference

Concepts

Other Resources