%N pgerrx %F $MIR/src/pgerrx.f
%D Horizontal error bar
%B
      SUBROUTINE PGERRX (N, X1, X2, Y, T)
      INTEGER N
      REAL X1(*), X2(*), Y(*)
      REAL T

 Plot horizontal error bars.
 This routine draws an error bar only; to mark the data point in
 the middle of the error bar, an additional call to PGPT or
 PGERRY is required.

 Arguments:
  N      (input)  : number of error bars to plot.
  X1     (input)  : world x-coordinates of lower end of the
                    error bars.
  X2     (input)  : world x-coordinates of upper end of the
                    error bars.
  Y      (input)  : world y-coordinates of the data.
  T      (input)  : length of terminals to be drawn at the ends
                    of the error bar, as a multiple of the default
                    length; if T = 0.0, no terminals will be drawn.

 Note: the dimension of arrays X1, X2, and Y must be greater
 than or equal to N. If N is 1, X1, X2, and Y may be scalar
 variables, or expressions, eg:
       CALL PGERRX(1,X-SIGMA,X+SIGMA,Y)
