epoll_wait
Implemented in Antinomie 0.7.0 · Syscall list
Synopsis
Section titled “Synopsis”long epoll_wait(int epfd, struct epoll_event *events, int maxevents, int timeout);| Number (x86-64) | 232 |
| ABI | common |
| Kernel entry point | sys_epoll_wait |
This is the raw kernel prototype from the pinned Linux 6.12.94 schema, not the libc wrapper.
Description
Section titled “Description”Waits for events on an epoll instance and returns them in an array.
Arguments
Section titled “Arguments”| Name | Type | Meaning |
|---|---|---|
epfd (arg0) |
int |
File descriptor of an epoll instance. |
events (arg1) |
struct epoll_event * |
Pointer to an array of event structures, or an event mask. |
maxevents (arg2) |
int |
Maximum number of events to return. |
timeout (arg3) |
int |
Timeout, as a pointer to a time structure or a value in the unit the call uses. |
Return value
Section titled “Return value”On success: the number of ready events, 0 on timeout.
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
Section titled “Common errors”| Raw return | Name | Meaning |
|---|---|---|
-9 |
EBADF |
A file descriptor is not valid for this operation. |
-4 |
EINTR |
The call was interrupted by a signal. |
-22 |
EINVAL |
An argument is invalid. |
Man page
Section titled “Man page”Captured by Antinomie
Section titled “Captured by Antinomie”Coverage mark: Implemented. Every pointer argument has a capture rule in the pinned kernel patch and none of them records a “no decoder”, “address only” or “not observed” gap on any code path. Individual values can still be incomplete on a particular call; see the capture statuses.
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
Section titled “Arguments”| Argument | When | How | Recorded field key | Condition |
|---|---|---|---|---|
epfd (arg0) |
Entry | raw scalar word | args.0, args.epfd |
|
events (arg1) |
Entry | the pointer itself, as a raw word | args.1, args.raw[1] |
|
| ↳ pointee | Exit | array of epoll_event, count min(result, maxevents) |
arg1.epoll_events |
result is 0 or greater |
maxevents (arg2) |
Entry | raw scalar word | args.2, args.maxevents |
|
timeout (arg3) |
Entry | raw scalar word | args.3, args.timeout |
Filter fields
Section titled “Filter fields”- Result:
ret,syscall.errno,syscall.success,syscall.duration_ns. - Argument words:
args.epfd(arg0),args.events(arg1),args.maxevents(arg2),args.timeout(arg3);args.0toargs.5by position. - Structure
epoll_event[]behindevents(arg1):args.events.<member>fordata,events.
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.