QMReplace()

The QMReplace() function replaces the content of a field, value or subvalue in a dynamic array. It is analogous to the QMBasic REPLACE() function.

Format

VB	QMReplace(ByVal Src as String, ByVal Fno as Integer, ByVal Vno as Integer, ByVal Svno as Integer, ByVal NewData as String) as String

C	char * QMReplace(char * Src, int Fno, int Vno, int Svno, char * NewData as String)

where

Src	is the dynamic array to be processed

Fno	is the number of the field to be replaced. If zero, 1 is assumed. If negative, a new field is appended to the dynamic array.

Vno	is the number of the value to be replaced. If zero, the entire field is inserted. If negative, a new value is appended to the specified field.

Svno	is the number of the subvalue to be replaced. If zero, the entire value is inserted. If negative, a new subvalue is appended to the specified value.

NewData

is the new data to form the new dynamic array element.

The QMReplace() function returns a new dynamic array with the specified field, value or subvalue replaced.

Note that in the C API library, a statement of the form

rec = QMReplace(rec, 2, 0, 0, new_data)

will return a pointer to a newly allocated memory area, overwriting the rec pointer. The old memory is not freed by this call and it is therefore necessary to retain a pointer to the original rec string so that it can be freed later.

This function is evaluated on the client system and does not require a server connection to be open.

Examples

Rec = QMReadu(fClients, ClientNo, True, ErrNo)

Rec = QMReplace(Rec, 1, Pos, 0, NewData)

QMWrite fClients, ClientNo, Rec

Rec = QMReadu(fClients, ClientNo, TRUE, ErrNo);

Rec2 = QMReplace(Rec, 1, Pos, 0, NewData);

QMWrite(fClients, ClientNo, Rec2);

QMFree(Rec);

QMFree(Rec2);

The above program fragment reads a record with an update lock, uses QMReplace() to modify it and then writes it back to the file. A real program should test the ErrNo status from the read operations to determine if they were successful.

Note how the C example uses QMFree() to release the dynamic memory allocated to store Rec and Rec2.