Macro introduces \par in Table of Contents

[Christopher Dimech]

I have written the macro uSubSec

However I have found that a \par is introduced in the Table of Contents
when the title continues on the next line. How can this problem be solved?

Example:

@uSubSec{@value{SecLb}, Probabilistic Characterisation of
Microseismicity}

@macro uSubSec{label, titl}

  @set lb \label\
  @ifclear USubSec--No--Label
    @unnumberedsubsec @value{lb} @ \titl\
  @end ifclear

  @ifset USubSec--No--Label
    @unnumberedsubsec \titl\
  @end ifset

@end macro