Re: [PATCH v2] recv.2: Document MSG_CMSG_CLOEXEC as returned in msg_flags
From: Alejandro Colomar <alx@kernel.org>
Date: 2023-07-17 23:11:20
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Hi Matthew, On 2023-07-17 01:47, Matthew House wrote:
quoted hunk
Signed-off-by: Matthew House <redacted> --- Clarified that the argument comes from the recvmsg() call. It feels a bit redundant to name recvmsg() again here, given that the list of flags is immediately preceded by, "The msg_flags field in the msghdr is set on return of recvmsg(). It can contain several flags: [...]" But I'll let you be the judge of that. man2/recv.2 | 9 +++++++++ 1 file changed, 9 insertions(+)diff --git a/man2/recv.2 b/man2/recv.2 index 660c103fb..1cd9f3e1b 100644 --- a/man2/recv.2 +++ b/man2/recv.2@@ -412,6 +412,15 @@ is returned to indicate that expedited or out-of-band data was received. .B MSG_ERRQUEUE indicates that no data was received but an extended error from the socket error queue. +.TP +.BR MSG_CMSG_CLOEXEC " (since Linux 2.6.23)" +.\" commit 4a19542e5f694cd408a32c3d9dc593ba9366e2d7 +indicates that +.B MSG_CMSG_CLOEXEC +was specified in the +.I flags +argument of +.BR recvmsg ().
I don't understand what's the purpose of this. The kernel sets a bit just to report to the caller that it set a bit? No other purpose? It feels very weird. Of course, the caller already has that info, doesn't it? Thanks, Alex
.SH RETURN VALUE These calls return the number of bytes received, or \-1 if an error occurred.
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