* c-exp.y (exp): Add unary plus. * eval.c (evaluate_subexp_standard): Add UNOP_PLUS case. * valarith.c (value_x_unop): Add UNOP_PLUS case. (value_pos): New. * value.h (value_pos): Declare. * gdb.cp/userdef.cc (A1::operator+): New unary plus. (A2): New class. (main): Test operator+. * gdb.cp/userdef.exp: Test unary plus. Use A2::operator+ for breakpoint test.