Copyright Digital Equipment Corp. All rights reserved.
Return_Values
n Upon successful completion, the value returned
depends on the value of the request argument
as follows:
o F_DUPFD - Returns a new file descriptor.
o F_GETFD - Returns FD_CLOEXEC or 0.
o F_SETFD, F_GETLK, F_SETLK, F_UNLCK - Return
a value other than -1.
-1 Indicates that an error occurred. The function
sets errno to one of the following values:
o EACCES - The request argument is F_SETLK;
the type of lock (l_type) is a shared (F_
RDLCK) or exclusive (F_WRLCK) lock, and the
segment of a file to be locked is already
exclusive-locked by another process; or
the type is an exclusive (F_WRLCK) lock and
the some portion of the segment of a file
to be locked is already shared-locked or
exclusive-locked by another process.
o EBADF - The file_desc argument is not a
valid open file descriptor and the arg
argument is negative or greater than or
equal to the per-process limit.
The request parameter is F_SETLK or F_
SETLKW, the type of lock (l_type) is a
shared lock (F_RDLCK), and file_desc is not
a valid file descriptor open for reading.
The type of lock (l_type) is an exclusive
lock (F_WRLCK), and file_desc is not a
valid file descriptor open for writing.
o EFAULT - The arg argument is an invalid
address.
o EINVAL - The request argument is F_DUPFD
and arg is negative or greater than or
equal to OPEN_MAX.
Either the OPEN_MAX value or the per-
process soft descriptor limit is checked.
An illegal value was provided for the
request argument.
The request argument is F_GETLK, F_SETLK,
or F_SETLKW and the data pointed to by arg
is invalid, or file_desc refers to a file
that does not support locking.
o EMFILE - The request argument is F_DUPFD
and too many or OPEN_MAX file descriptors
are currently open in the calling process,
or no file descriptors greater than or
equal to arg are available.
Either the OPEN_MAX value or the per-
process soft descriptor limit is checked.
o EOVERFLOW - One of the values to be
returned cannot be represented correctly.
The request argument is F_GETLK, F_SETLK,
or F_SETLKW and the smallest or, if l_
len is nonzero, the largest offset of any
byte in the requested segment cannot be
represented correctly in an object of type
off_t.
o EINTR - The request argument is F_SETLKW,
and the function was interrupted by a
signal.
o ENOLCK - The request argument is F_SETLK or
F_SETLKW, and satisfying the lock or unlock
request would exceed the configurable
system limit of NLOCK_RECORD.
o ENOMEM - The system was unable to allocate
memory for the requested file descriptor.