readahead

Implemented in Antinomie 0.7.0 · Syscall list

Synopsis

long readahead(int fd, loff_t offset, size_t count);

Number (x86-64)	187
ABI	common
Kernel entry point	sys_readahead

This is the raw kernel prototype from the pinned Linux 6.12.94 schema, not the libc wrapper.

Description

Asks the kernel to load a range of a file into the page cache.

Arguments

Name	Type	Meaning
fd (arg0)	int	File descriptor to operate on.
offset (arg1)	loff_t	Value of type loff_t.
count (arg2)	size_t	Number of bytes, or number of entries.

Return value

On success: 0.

In an Antinomie trace the Return column and the ret filter field show the raw kernel return value. On failure that is the negative errno, for example -2 for ENOENT, not the -1 plus errno that the libc wrapper gives. syscall.errno holds the positive errno and syscall.success is false.

Common errors

Raw return	Name	Meaning
-9	EBADF	A file descriptor is not valid for this operation.
-22	EINVAL	An argument is invalid.

Man page

readahead(2) on man7.org

Captured by Antinomie

Coverage mark: Implemented. All arguments are plain values, recorded as the raw argument words at entry. There is no pointee to copy and no known gap.

Every call is recorded as an Entry record (the six argument words and the pointees copied at entry) and an Exit record (the return value and the pointees copied at exit).

Arguments

Argument	When	How	Recorded field key	Condition
fd (arg0)	Entry	raw scalar word	args.0, args.fd
offset (arg1)	Entry	raw scalar word	args.1, args.offset
count (arg2)	Entry	raw scalar word	args.2, args.count

Filter fields

• Result: ret, syscall.errno, syscall.success, syscall.duration_ns.
• Argument words: args.fd (arg0), args.offset (arg1), args.count (arg2); args.0 to args.5 by position.

See Syscall Trace filter for the full syntax.

For what the capture statuses mean, see Capture statuses. For what is never recorded, see Known gaps.