# Omgevingsvariabelen

/// tip

Als je al weet wat "omgevingsvariabelen" zijn en hoe je ze kunt gebruiken, kun je deze stap gerust overslaan.

///

Een omgevingsvariabele (ook bekend als "**env var**") is een variabele die **buiten** de Python-code leeft, in het **besturingssysteem** en die door je Python-code (of door andere programma's) kan worden gelezen.

    while (true) {
      if (peek == null) {
        peek = readToken()
        if (skipCommasAndWhitespace()) break // We peeked a scheme name followed by ','.
        eqCount = skipAll('='.code.toByte())
      }
      if (eqCount == 0) break // We peeked a scheme name.
      if (eqCount > 1) return // Unexpected '=' characters.
      if (skipCommasAndWhitespace()) return // Unexpected ','.

     * Gets the length of the first message in the pipe
     * @return the messageLength
     */
    public int getMessageLength() {
        return this.messageLength;
    }

    /**
     * Gets the data peeked from the pipe
     * @return the data
     */
    public byte[] getData() {
        return this.data;
    }

    /**
     * {@inheritDoc}
     *
     * @see Decodable#decode(byte[], int, int)
     */

  /**
   * Returns a value from this adapter.
   *
   * This must always return a value, though it doesn't necessarily need to consume data from
   * [reader]. For example, if the reader's peeked tag isn't readable by this adapter, it may return
   * a default value.
   *
   * If this does read a value, it starts with the tag and length, and reads an entire value,
   * including any potential composed values.
   *