The FORTRAN level-2 BLAS call for this operation is

SUBROUTINE SYR2 ( UPLO, N, ALPHA, X, INCX, Y, INCY, A, LDA )

Here is replaced by S, D, C, or Z
to indicate the datatype of the data (single, double, complex, double precision complex).
Parameter UPLO indicates whether A is
lower (UPLO = "Lower") or upper (UPLO = "Upper") triangular.
Parameter N holds the matrix dimension
n .
Parameter ALPHA holds the scaling factor .
Parameters A, X, and Y equal the
addresses of where matrix A and vectors x and y start in
memory. The leading dimension of the matrix is given in
LDA and the stride of the vectors in INCX and INCY.