Wrong file location by \IfFileExists

Question

The following code is the content of my main.tex.

The file a.tex is in the subdirectory tmp under the directory where main.tex is, that is to say: ./main.tex and ./tmp/a.tex.

The problem of my code is: \IfFileExists find the file ./tmp/a.tex. As there is no file ./a.tex, I think the typeset should be NO FILE. But the actual typeset is a.tex.

Is it a problem of my version of LaTex, MikTex, xelatex, auctex or any others?

PS: the subdirctory tmp is used to store those tmpt and aux files during compilation.

Code:

\documentclass{article}
\begin{document}
  \makeatletter
  \IfFileExists{a.tex}
  {\filename@parse{a.tex}\filename@area\filename@base.\filename@ext}
  {NO FILE}
  \makeatother
\end{document}

add \input{a.tex} and then look which file it actually find. — Ulrike Fischer, Jul 14 '22 at 07:33
There is no ./a.tex, but ./tmp/a.tex. \input{a.tex} causes ./tmp/a.tex loaded. — lyl, Jul 14 '22 at 07:37
oh your edit explains it: such a build folder is added to the search path. — Ulrike Fischer, Jul 14 '22 at 07:37
you can't. latex has to find the auxiliary there. If you would remove it from the path neither the tableofcontents nor the reference would work anymore. (I never use such a build folder, imho it only make things more complicated.) — Ulrike Fischer, Jul 14 '22 at 07:43
conditionals - Can I test if a file exists? - TeX - LaTeX Stack Exchange — user202729, Jul 14 '22 at 07:46
Is there any way to obtain the absolute path of a file in latex by which things may get easier? — lyl, Jul 14 '22 at 07:50
That's... a separate question? Absolute path of what file? If of current file see currfile package — user202729, Jul 14 '22 at 07:55
@user202729 That still reflects what TEXINPUTS provides: here, we'd get a.tex as it's on the search path — Joseph Wright, Jul 14 '22 at 08:18
the absolute path I mean is like /...../....../a.tex(from root path) — lyl, Jul 14 '22 at 08:31
@user202729 macros from Latex3 for full_name seem not output the absolute path(I mean from root path). — lyl, Jul 14 '22 at 08:38

score 3 · Answer 1 · edited Jul 14 '22 at 08:23

3

\IfFileExists tests "would \input work".

So as you say you have configured things so \input{a.tex} inputs a file, then the test is true.

It is not normally desirable (or possible) to know where in the input path the file is located. For example this test allows LaTeX to detect a missing package with \usepackage{mistake} but a working example such as \usepackage{longtable} works portably even though the absolute file path to longtable.sty is system dependent

edited Jul 14 '22 at 08:23

Joseph Wright

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answered Jul 14 '22 at 08:20

David Carlisle

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Does that parentheses mean "it's not normally possible" or absolute "it's not possible"? ■ Side note, what about with LuaTeX powers? – user202729 Jul 14 '22 at 09:54
@user202729 well you could use kpsewhich (which you can use without --shell-escape i most configurations) to get the full path. – David Carlisle Jul 14 '22 at 13:10
For reference, OP asked a new question on how to get the absolute path → https://tex.stackexchange.com/q/650955/250119 – user202729 Jul 16 '22 at 10:37

Wrong file location by \IfFileExists

1 Answers1