LDP
/
man-pages
mirror of https://github.com/mkerrisk/man-pages
0
1
Fork 0
Code Releases Activity

recv.2: Isolate details specific to recv() vs recvfrom() vs recvmsg() 

Place details specific to each system call under a
a separate subheading.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Michael Kerrisk 2014-02-11 10:27:19 +01:00
parent 7cb04a61d3
commit 183ec51374
1 changed files with 42 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

83
man2/recv.2
View File

@ -66,47 +66,6 @@ system calls are used to receive messages from a socket.
They may be used
to receive data on both connectionless and connection-oriented sockets.
.PP
If
.I src_addr
is not NULL, and the underlying protocol provides the source address,
this source address is filled in.
When
.I src_addr
is NULL, nothing is filled in; in this case,
.I addrlen
is not used, and should also be NULL.
.\" (Note: for datagram sockets in both the UNIX and Internet domains,
.\" .I src_addr
.\" is filled in.
.\" .I src_addr
.\" is also filled in for stream sockets in the UNIX domain, but is not
.\" filled in for stream sockets in the Internet domain.)
.\" [The above notes on AF_UNIX and AF_INET sockets apply as at
.\" Kernel 2.4.18. (MTK, 22 Jul 02)]
The argument
.I addrlen
is a value-result argument,
which the caller should initialize before the call to
the size of the buffer associated with
.IR src_addr ,
and modified on return to indicate the actual size of the source address.
The returned address is truncated if the buffer provided is too small;
in this case,
.I addrlen
will return a value greater than was supplied to the call.
.PP
The
.BR recv ()
call is normally used only on a
.I connected
socket (see
.BR connect (2))
and is identical to
.BR recvfrom ()
with a NULL
.I src_addr
argument.
.PP
All three routines return the length of the message on successful
completion.
If a message is too long to fit in the supplied buffer, excess
@ -280,7 +239,49 @@ satisfied.
However, the call may still return less data than requested if
a signal is caught, an error or disconnect occurs, or the next data to be
received is of a different type than that returned.
.SS recvfrom()
.PP
If
.I src_addr
is not NULL, and the underlying protocol provides the source address,
this source address is filled in.
When
.I src_addr
is NULL, nothing is filled in; in this case,
.I addrlen
is not used, and should also be NULL.
.\" (Note: for datagram sockets in both the UNIX and Internet domains,
.\" .I src_addr
.\" is filled in.
.\" .I src_addr
.\" is also filled in for stream sockets in the UNIX domain, but is not
.\" filled in for stream sockets in the Internet domain.)
.\" [The above notes on AF_UNIX and AF_INET sockets apply as at
.\" Kernel 2.4.18. (MTK, 22 Jul 02)]
The argument
.I addrlen
is a value-result argument,
which the caller should initialize before the call to
the size of the buffer associated with
.IR src_addr ,
and modified on return to indicate the actual size of the source address.
The returned address is truncated if the buffer provided is too small;
in this case,
.I addrlen
will return a value greater than was supplied to the call.
.SS recv()
The
.BR recv ()
call is normally used only on a
.I connected
socket (see
.BR connect (2))
and is identical to
.BR recvfrom ()
with a NULL
.I src_addr
argument.
.SS recvmsg()
The
.BR recvmsg ()
call uses a