How to use sockets with the Stand-Alone LWIP?

Sorry the answer is No. The use of the sockets API requires a threaded environment.

Below is the quote from the LWIP documentation, which can be found in the file rawapi.txt in the src/downloads/lwip-0.6.3/doc directory

Raw TCP/IP interface for lwIP 0.5

"lwIP provides two Application Program's Interfaces (APIs) for programs

to use for communication with the TCP/IP code: the sequential API

(often just called "the API") and the raw TCP/IP interface. This

document is intended as a description of the latter. For lwIP versions

lower than 0.5, this API was not documented.

The sequential API provides a way for ordinary, sequential, programs

to use the lwIP stack. It is quite similar to the BSD socket API. The

model of execution is based on the open-read-write-close

paradigm. Since the TCP/IP stack is event based by nature, the TCP/IP

code and the application program must reside in different execution

contexts (threads).

The raw TCP/IP interface allows the application program to integrate

better with the TCP/IP code. Program execution is event based by

having callback functions being called from within the TCP/IP

code. The TCP/IP code and the application program both run in the same

thread. The sequential API has a much higher overhead and is not very

well suited for small systems since it forces a multithreaded paradigm

on the application."