[Overview][Constants][Types][Procedures and functions][Variables][Index] | Reference for unit 'Unix' (#rtl)

# fpFlock

Lock a file (advisory lock)

## Declaration

Source position: unix.pp line 95

`function fpFlock(`
`var T: text;`
`mode: cint`
`):cint; function fpFlock(`
`var F: file;`
`mode: cint`
`):cint; function fpFlock(`
`fd: cint;`
`mode: cint`
`):cint;`

## Description

FpFLock implements file locking. it sets or removes a lock on the file F. F can be of type Text or File, or it can be a Linux file descriptor (a longint) Mode can be one of the following constants :

LOCK_SH
  sets a shared lock.
LOCK_EX
  sets an exclusive lock.
LOCK_UN
  unlocks the file.
LOCK_NB
  This can be OR-ed together with the other. If this is done the application doesn't block when locking.

The function returns zero if successful, a nonzero return value indicates an error.

## Errors

Extended error information is returned by the FpGetErrno function:

## See also

#rtl.baseunix.FpFcntl |  | File control operations.
FSync |  | Synchronize file's kernel data with disk.