SOCU:poll

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Request[edit]

Index Word Description
0 Header code [0x00140084]
1 nfds_t nfds
2 int timeout
3 Value 0x20 (processID header)
4 ProcessID set by the ARM11 kernel.
5 (insize<<14) | 0x2802
6 Pointer to input pollfd struct array

The following is located 0x100-bytes after the beginning of the above command buffer:

Index Word Description
0 (outsize<<14) | 2
1 Pointer to output pollfd struct array

Response[edit]

Index Word Description
0 Header code
1 Result code
2 POSIX return value

pollfd struct[edit]

Type Name Description
u32 fd Socket handle
u32 events Events to poll for (input)
u32 revents Events received (output)

Events[edit]

Events are a bitwise set of these flags. These flags don't exactly match the Wii flags, even though the sockets sysmodule uses the same codebase.

Value Name Description
0x01 POLLIN Data can be read.
0x02 POLLPRI Urgent data can be read.
0x08 POLLWRNORM Normal data can be written.
0x10 POLLWRBAND Priority data can be written.
0x20 POLLNVAL Invalid socket handle.
POLLWRNORM POLLOUT Data can be written.

Flag 0x4 isn't ever assigned in the code. Flags 0x40 and 0x80 are also not used, even though they are assgined in the input events by default along with 0x20. This is likely because that code section was inherited from the Wii, where these flags are used for poll errors.

Contrary to the Wii sockets, the 3DS doesn't have POLLERR or POLLHUP, so poll shouldn't be relied on when checking for socket errors.