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  • Locks set by HNoModif
  • Miscellaneous
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Stored procedures
HNoModif (Function)
In french: HInterditModif
ODBCNot available with this kind of connection
Forbids all the modifications on a data file (for all the programs, including the one that requested the no-modification policy). The records can be accessed in read-only.
WEBDEV - Server code The restriction is performed for all the sessions and other programs (developed with WEBDEV), including the session that requested the restriction.
// Process...
<Result> = HNoModif(<Data file>)
<Result>: Boolean
  • True if no problem occurred,
  • False otherwise. HError returns more details about the problem.
If the data file is still locked after H.NbRetry attempts, HErrorLock returns True (the H.Locked variable is set to True).
If the data file was locked, HErrorLock returns False.
<Data file>: Character string
Name of the data file used.

Locks set by HNoModif

HNoModif can lock in write mode a file already locked by another program (with HNoModif). Therefore, several programs can forbid the modifications on the same data file at the same time. A locking read function run after HNoModif in the same program reads the record without locking it.
HNoModif cannot lock a data file already locked in read/write by another program.
Reminder: the data file cannot be locked by HNoModif only if the data file is locked in read/write by another program.
  • In single-user mode (HMode), HNoModif is equivalent to HOpen (the data files are locked in read/write as soon as they are opened).
  • You have the ability to lock a data file whose records are locked by another application.


The maximum number of programs that can request the no-modification policy on a data file depends on the size of a record in the data file. It can be calculated as follows:
MaxNbSessionsOrPrograms = RecordSize - 20
Component: wd300hf.dll
Minimum version required
  • Version 9
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Last update: 07/03/2023

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