Cdtrjyty

At a certain position in the article, the page that it belongs, need a special fancy style which I do by thispagestyle from the package fancyhdr.

In my example as shown in the MWE below, the page, and only the page where the text "bbb" is in(it's at the second page in this example, but may also at the other page, determined by the length of article), need a chead. However, the content of chead is in fact at the first page, not in the second page as I expect.

I think this is because no page-break is given. But the position of text "bbb" is up to the length of article, so how to deal with this problem?

My MWE is:

documentclass{article}

usepackage{fancyhdr}



begin{document}

fancypagestyle{common}{chead{I want my header only on the page at which  ``bbb'' is located}}

aaaparvspace{80em}

bbbthispagestyle{common}parvspace{80em}

ccc

end{document}

You can use a mark command:

documentclass{article}

usepackage{fancyhdr}

fancypagestyle{common}{fancyhf{}chead{rightmark}}

pagestyle{common}

begin{document}



aaaparvspace{80em}

bbbmarkright{I want my header only on the page at which  ``bbb'' is located}markright{}parvspace{80em}

ccc

end{document}

I guess you're using headers, but that's not really relevant.

The problem is that page breaking is asynchronous: typically TeX reads more that fits in a page before deciding it has to ship out a page. In your case, thispagestyle is seen and processed while TeX has not yet decided to eject page 1.

The command thispagestyle is only reliable if given shortly after a page break, for instance when a new chapter is started, a feature which standard classes use for issuing thispagestyle{plain}.

The only reliable method is to use the label-pageref mechanism. Here I implement the job with the help of refcount that provides an expandable version of pageref, namely getpagerefnumber.

documentclass{article}

usepackage{fancyhdr}

usepackage{refcount,pdftexcmds}



pagestyle{fancy}



makeatletter

chead{%

  ifnumpdf@strcmp{thepage}{getpagerefnumber{bbb}}=z@

    I want my header only on the page at which  ``bbb'' is located%

  else

    Normal header%

  fi

}

makeatother



begin{document}



aaaparvspace{80em}

bbblabel{bbb}parvspace{80em}

ccc



end{document}

I use pdf@strcmp in order to ensure that any kind of page numbering is supported.