| title | `\spacefactor` complaints |
|---|---|
| category | errors |
| permalink | /FAQ-atvert |
The errors
! You can't use `\spacefactor' in vertical mode.
\@->\spacefactor
\@m or
! You can't use `\spacefactor' in math mode.
\@->\spacefactor
\@m or simply
! Improper \spacefactor.
...bite the LaTeX programmer who uses an internal command without
taking "precautions". An internal-style command such as \@foo
has been defined or used in a private macro, and it is interpreted as
\@, followed by the "text" foo. (\@ is used, for
real, to set up end-of-sentence space in some circumstances; it uses
\spacefactor to do that.)
The problem is discussed in detail in
"@ in macro names",
together with solutions.