The FORTRAN level-2 BLAS call for this operation is

SUBROUTINE SYR ( UPLO, N, ALPHA, X, INCX, 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 stored in the
lower (UPLO = "Lower") or upper (UPLO = "Upper") triangular part of A.
Parameter N holds the matrix dimension
n .
Parameter ALPHA holds the scaling factor .
Parameters a and x equal the
addresses of where matrix A and vector x start in
memory. The leading dimensions of the matrix is given in
LDA and the stride of the vector in INCX.