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calculateDiscriminator

Calculates the 8-byte discriminator for an instruction in a Solana program written with the Anchor framework. Anchor prefixes all instruction data with a unique 8-byte hash to identify which function to call. This hash is the first 8 bytes of sha256("global:<function_name>").

This function simplifies interaction with Anchor-based programs.

Parameters​

ParameterTypeDescription
functionNameconst std::string&The name of the Anchor instruction function (e.g., "initialize" or "update_data").

Return Value​

  • std::vector<uint8_t>: An 8-byte vector containing the calculated discriminator.

Example Code (main.cpp)​

#include <Arduino.h>
#include "Infratic-lib.h"

const String SOLANA_RPC_URL = "[https://api.devnet.solana.com](https://api.devnet.solana.com)";
Infratic solana(SOLANA_RPC_URL);

void setup() {
    Serial.begin(115200);
    delay(1000);

    Serial.println("\n=== Calculate Anchor Discriminator Example ===");

    std::string functionName = "update_temperature";
    std::vector<uint8_t> discriminator = solana.calculateDiscriminator(functionName);

    Serial.print("✅ Discriminator for '");
    Serial.print(functionName.c_str());
    Serial.print("' (hex): ");
    for (uint8_t b : discriminator) {
        if (b < 16) Serial.print("0");
        Serial.print(b, HEX);
        Serial.print(" ");
    }
    Serial.println();
}

void loop() {
    // Can be left empty
}