I'm looking for the StreamSend.h library for use in Arduino/ESP8266 serial communications using struct

Projects Programming
2

The simplest way is to use a number of Serial.print (one for each variable) to send the variables as text and use e.g. a comma as the separator. You can have a look at Serial Input Basics - updated for the receiving side and write a matching function for the sending side.

The sending of binary data is simple; cast to a byte pointer and use serial.write. Below demonstrates

struct MYDATA
{
  char text[10];
  byte aByte;
};

MYDATA dataToSend =
{
  "abc",
  0x30  // 
};

void setup()
{
  Serial.begin(57600);
  Serial.write((byte*)&dataToSend, sizeof(dataToSend));
}

void loop()
{
}

(byte*) is the cast, & indicates the address of the variable dataToSend.

There are some pitfalls

  1. Sending binary data of variables like int has a dependency on the the endianness of the two systems. Sending text is easier from that perspective.
  2. Synchronisation of binary data is more complex than of text. Reason is that it's more difficult to differentiate between actual data and a 'beginning fo packet'.