ztrmm(3) on Linux
The text 377783d7a805, as Debian 3.0 (Woody), Debian 1.3 (Bo) shipped it.
perform one of the matrix-matrix operations B := alpha*op( A )*B, or B := alpha*B*op( A ) where alpha is a scalar, B is an m by n matrix, A is a unit, or non-unit, upper or lower triangular matrix and op( A ) is one of op( A ) = A or op( A ) = A' or op( A ) = conjg( A' )