recvfrom(2)
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recvfrom System Call
Receive a message from a socket.
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SYNTAX
#include <socket.h>
int recvfrom (s, buf, len, user_flags, from, fromlen)
int s;
char * buf;
int len;
int user_flags;
struct sockaddr *from;
int * fromlen;
PARAMETERS
s File descriptor of socket to receive a message
from.
buf Buffer for message.
len Length of buffer.
user_flags Flags for transfer.
from Structure to hold sender's name.
fromlen On input contains the number of bytes available
for the sender's name; updated to indicate the
number of bytes returned.
DESCRIPTION
This call is identical to the recv call with the addition of
returning the name of the socket from which the message was sent.
When using recvfrom on connected sockets the <from> and <fromlen>
arguments will be undefined. When reading from datagram sockets,
messages that are longer than the buffer are truncated. See
recv(2) for additional information about the socket receive
mechanism.
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recvfrom(2)
ACCESS CONTROL
None.
RETURN VALUE
These calls return the number of bytes received.
1..<len> Number of bytes transferred.
-1 An error occurred. Errno is set to indicate the
error.
EXCEPTIONS
Errno may be set to one of the following error codes:
EBADF The argument <s> is not an active valid
descriptor.
ENOTSOCK The argument <s> is not a socket.
EAGAIN The socket is marked non-blocking and the receive
operation would block.
EINTR The receive was interrupted by delivery of a
signal before any data was available for the
receive.
EFAULT The data was specified to be received into a non-
existent or protected part of the process address
space.
EINVAL Bad argument.
SEE ALSO
The related manual sections: read(2), recv(2), send(2),
socket(2).
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