Function SCIPshowExpr 

pub unsafe extern "C" fn SCIPshowExpr(
    scip: *mut SCIP,
    expr: *mut SCIP_EXPR,
) -> SCIP_RETCODE

shows a single expression by use of dot and gv

This function is meant for debugging purposes. It’s signature is kept as simple as possible to make it easily callable from gdb, for example.

It prints the expression into a temporary file in dot format, then calls dot to create a postscript file, then calls ghostview (gv) to show the file. SCIP will hold until ghostscript is closed.