—it is equally true that `function of the writ***[is] not merely to restrain an unwarranted assumption of jurisdiction, but also to restrain an inferior court from exceeding its authorized powers in a proceeding over which it has jurisdiction

—it follows that it may not be employed to vacate a judgment even though, to quote from an opinion of this court, such judgment had been "procured as the result of a trial during the course of which rulings were made in violation of constitutional right*** if there was a right to review such rulings on an appeal from the judgment

It is well settled that prohibition is the traditional remedy to determine whether a lower court is exceeding its jurisdiction

—the court stated that the use of the writ of error coram nobis has been limited to errors of fact not apparent on the face of the record

Prohibition is an extraordinary remedy issued in the sound discretion of the court where the grievance cannot be redressed by ordinary proceedings at law or in equity

" `Judicial interference with the right to counsel guaranteed to defendant by law may warrant the extraordinary remedy of coram nobis, even though the error appears on the face of the record

—are denied relief from the unsatisfied claim and judgment fund and only those who can be classified as "qualified" persons are allowed relief under the fund

Section 2255 is available only to "a prisoner in custody" while coram nobis is available to persons in or out of confinement. Eg, State ex rel.