def vlcom3(a, v1, b, v2, c, v3):
    """
    This subroutine computes the vector linear combination
    a*v1 + b*v2 + c*v3 of double precision, 3-dimensional vectors.

    http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/vlcom3_c.html

    :param a: Coefficient of v1 
    :type a: float
    :param v1: Vector in 3-space 
    :type v1: 3-Element Array of floats
    :param b: Coefficient of v2 
    :type b: float
    :param v2: Vector in 3-space 
    :type v2: 3-Element Array of floats
    :param c: Coefficient of v3 
    :type c: float
    :param v3: Vector in 3-space 
    :type v3: 3-Element Array of floats
    :return: Linear Vector Combination a*v1 + b*v2 + c*v3
    :rtype: 3-Element Array of floats
    """
    v1 = stypes.toDoubleVector(v1)
    v2 = stypes.toDoubleVector(v2)
    v3 = stypes.toDoubleVector(v3)
    sumv = stypes.emptyDoubleVector(3)
    a = ctypes.c_double(a)
    b = ctypes.c_double(b)
    c = ctypes.c_double(c)
    libspice.vlcom3_c(a, v1, b, v2, c, v3, sumv)
    return stypes.cVectorToPython(sumv)