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TestFileNbr
Determine the status of a file number.
Short Name
TSTFILNUM()
Type
Low-Level function
Declaration
COUNT TestFileNbr(FILNO filno)
Description
In V12 the file number typedef was formally changed from COUNT, a two-byte value to FILNO, a four-byte value. Refer to this link for compatibility details. Four Byte File Numbering
TestFileNbr() returns zero if filno is not in use or returns FINT_ERR (47, c-tree not initialized), FNUM_ERR (22, filno is out of range), or FUSE_ERR (46, filno is in use). TestFileNbr() does NOT set or change uerr_cod.
Return
Value |
Symbolic Constant |
Explanation |
|---|---|---|
0 |
NO_ERROR |
File number not in use. |
22 |
FNUM_ERR |
filno is out of range. |
46 |
FUSE_ERR |
filno is in use. |
47 |
FINT_ERR |
c-tree not initialized. |
See c-tree Error Codes for a complete listing of valid c-tree error values.
Example
COUNT retval;
if (retval = InitISAM(6,7,4))
printf("\nCould not initialize. Error %d.", retval);
else {
if ((retval = TestFileNbr(5)) == 0) {
if (OpenRFile(5, "MyFile.dat"))
printf("\nCould not open files.");
{
else if (retval == 46)
if (OpenRFile(-1, "MyFile.dat"))
printf("\nCould not open files.");
if (CloseISAM())
printf("\nCould not close ISAM.");
}
