ESP32 Forum

Hello,


I would like to know where I could find the information of the lwip/sockets.h?

I am using this function:
ssize_t sizeRead = recv(clientSock, data + sizeUsed, total-sizeUsed, 0);

I go to the web of esp-idf and all the info that I can find is:
https://github.com/espressif/esp-idf/bl ... /sockets.h
int lwip_recv(int s, void *mem, size_t len, int flags);

I would like to know what is flags??


B.R.

Hi B.R.,

You're right that we don't have documentation for the LWIP sockets interface in ESP-IDF right now. We can look into adding it in the future.

This interface is intended to be compatible with the "BSD Sockets" (aka "Berkely Sockets" or "POSIX Sockets") interface, which is used on all Unix-like operating systems, and available on most other operating systems (ie Windows) even though it's not the default.

A good standard reference is this one from the Single UNIX Specification. If you click on "recv" then you can see the available flags for the recv() function. I sometimes refer to Linux man pages as well (although Linux often has a number of additional features not in the common implementation).