# %recvfrom() function

The %recvfrom() function receives a
datagram from a bound socket and stores the information on the sender.
If no errors occur, the number of bytes received is returned.

## Syntax

```
code = %recvfrom(socket, buffer, bufferLength, flags, &sourceAddress, &port)
```

## Parameter(s)

| socket | File descriptor for the local socket. |
| --- | --- |
| buffer | Data to be received. |
| bufferLength | Maximum length of the buffer. |
| flags | Should be zero. |
| sourceAddress | Address of the sender. |
| port | Port number of the sender. |

## Example(s)

```
*
* Open a connection through UDP/IP.
* recv packets from the network execute the command
* and send result packets back
*
cfunction socket.builtin
include dm,bp,includes sysid.inc
include dm,bp,unix.h socket.h
equ ip_port to 3176
*
* Create a socket
fd=%socket( AF$INET, SOCK$DGRAM, 0)
if fd<0 then print "Error opening socket ":system(0); stop
*
* Bind the socket to an ethernet port
port=%bind( fd, AF$INET, INADDR$ANY, ip_port )
*
* Read buffers to get the command to execute
packcnt = 0
bigbuff = ""
loop
 addr=0; port=0
 buffer = space(256)
 length=%recvfrom( fd, buffer, 256, 0, &addr, &port)
 if length<0 then print "Read Error: ":system(0)
 PackSeq = buffer[5,4]
 MaxPack = buffer[9,4]
 packcnt += 1
 bigbuff[1+((PackSeq-1)*242),242] = buffer[13,242]
until packcnt = MaxPack do repeat
*
* execute the command
execute bigbuff capturing ret
*
* get the byteswapped remote address
remhost = ""
addr = dtx(addr)
lad = len(addr)
addr = xtd(addr[lad-7,8])
for x = 1 to 4
 part = rem(addr,256)
 addr = int(addr/256)
 remhost<-1>= part
next x
convert @AM to &#39;.&#39; in remhost
*
ln = len(ret)
MaxPack = int(ln/242)+1
for x = 1 to MaxPack
 Buffer = "RETC":x &#39;r%4&#39;:MaxPack &#39;r%4&#39;:ret[((x-1)*242)+1,242]:space(242)
 n = %sendto(fd, Buffer, 256, 0, &remhost, ip_port)
 if n < 0 then
 print "Write error: ":system(0)
 end
next x
*
* Close the socket
%close( fd )
```

---
Source: https://d3codex.com/pickbasic-flashbasic/percent-recvfrom-function/ - part of the D3Codex reference.