How can I write an integral with a symbol of cross (“x”) over the integral?

Question

The integral that I want to write is the integral cross, I want to put an “x” on the integral...

Answer 1

If you use lualatex/xelatex, you can load some font that has the slot u+02A18, which can be accessed by \intx. The New Computer Modern font has it (I use the nice slightly bolder version below).

\documentclass{article}
\usepackage{unicode-math}
\setmainfont{NewCM10-Book.otf}
\setmathfont{NewCMMath-Book.otf}
\begin{document}
[\intx_G f(x), d\mu(x)]
\end{document} 

Result:

Answer 2

Shamelessly borrowing (stealing?) some code from the posting The Principal Value Integral symbol on the TeX-FAQ site, here's a suggestion for a directive called \intmult -- short for "multiplicative integral".

IMNSHO, I think that this version of the multiplicative integral symbol actually looks a lot better than the one in the paper by Dasgupta. (In the Dasgupta paper, the intersection of the \times symbol does not lie on top of the integral symbol.)

\documentclass{article}
% The following code is copied from https://texfaq.org/FAQ-prinvalint
\def\Xint#1{\mathchoice
   {\XXint\displaystyle\textstyle{#1}}%
   {\XXint\textstyle\scriptstyle{#1}}%
   {\XXint\scriptstyle\scriptscriptstyle{#1}}%
   {\XXint\scriptscriptstyle\scriptscriptstyle{#1}}%
   !\int}
\def\XXint#1#2#3{{\setbox0=\hbox{$#1{#2#3}{\int}$}
     \vcenter{\hbox{$#2#3$}}\kern-.5\wd0}}
\def\intmult{\Xint\times}
\begin{document}
$\displaystyle\intmult_0^1 \quad \textstyle\intmult_0^1$ \qquad vs.\qquad
$\displaystyle\int_0^1 \quad \textstyle\int_0^1$
\end{document}

Answer 3

There is also a possibility to use stix font. I remember that stix font change all the math-font of the whole tex document. Alternatively you can declare only the symbol of the integral, but I think that this is not a good approach.

\documentclass[a4paper,12pt]{article}
\usepackage{stix}
\usepackage{mathtools}
\begin{document}
\[\intx_C f(z)dz\]
$\intx_C f(z)dz$
\end{document}

Alternatively you can use a primitive simple syntax using \kern.

\documentclass[12pt]{article}
\usepackage{mathtools,amssymb}
\begin{document}
$\int_D\kern-1.2em\scriptstyle \times\kern.5em f(z)dz$
[\int_D\kern-1.1em\scriptstyle \times\kern.5em f(z)dz]
\end{document}