title: Why will this R package not install and how can I fix it?
body: <p>I would like to include a Fortran subroutine in an R package. I have always only built packages using devtools and roxygen (so my knowledge may be pretty limited). I am getting an error that prevents me from the package getting installed after it has been built about it not being a Win32 application...</p>
  
  <p>I am using Rtools 3.3. My session info:</p>
  
  <pre><code>&gt; sessionInfo()
  R version 3.2.2 (2015-08-14)
  Platform: x86_64-w64-mingw32/x64 (64-bit)
  Running under: Windows 7 x64 (build 7601) Service Pack 1
  
  locale:
  [1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252    LC_MONETARY=English_United States.1252
  [4] LC_NUMERIC=C                           LC_TIME=English_United States.1252    
  
  attached base packages:
  [1] stats     graphics  grDevices utils     datasets  methods   base     
  
  other attached packages:
  [1] roxygen2_5.0.1 devtools_1.9.1
  
  loaded via a namespace (and not attached):
  [1] magrittr_1.5  tools_3.2.2   Rcpp_0.12.1   memoise_0.2.1 stringi_1.0-1 stringr_1.0.0 digest_0.6.8 
  </code></pre>
  
  <p>To initially build the package, I run this:</p>
  
  <pre><code>library(devtools)
  library(roxygen2)
  
  setwd("C:/panterasBox")
  create("myPack")
  setwd("C:/panterasBox/myPack")
  dir.create("C:/panterasBox/myPack/src")
  </code></pre>
  
  <p>This is the fortran code, saved as myFunc.f in the <code>/src</code> file:</p>
  
  <pre><code>         subroutine myFunc(x)
           implicit none
           real(8) x
  
           x = x + 2
  
           return
           end
  </code></pre>
  
  <p>The R wrapper I am using to call it (saved in the <code>/R</code> file):</p>
  
  <pre><code>#' @title A test
  #' @description a test function.
  #' @param x this is a number
  #' @useDynLib myPack
  #' @export
  myFunc &lt;- function(x){
    if (!is.loaded('myFunc')) {
      dyn.load("/src/myPack.dll")
    }
    myCall &lt;- NULL
    myCall &lt;- .Fortran("myFunc", x=as.double(x), PACKAGE="myPack")
    return(myCall$x)
  }
  </code></pre>
  
  <p>Now, to create the documentation and install the package, I run this:</p>
  
  <pre><code>&gt; document()
  Updating myPack documentation
  Loading myPack
  Re-compiling myPack
  "C:/Users/pantera/DOCUME~1/R/R-32~1.2/bin/x64/R" --no-site-file --no-environ --no-save --no-restore CMD INSTALL  \
  "C:\panterasBox\myPack" --library="C:\Users\pantera\AppData\Local\Temp\RtmpQdJJko\devtools_install_1df837dd6c29" --no-R  \
  --no-data --no-help --no-demo --no-inst --no-docs --no-exec --no-multiarch --no-test-load 
  
  * installing *source* package 'myPack' ...
  ** libs
  gfortran -m64     -O2  -mtune=core2 -c myFunc.f -o myFunc.o
  gcc -m64 -shared -s -static-libgcc -o myPack.dll tmp.def myFunc.o -Ld:/RCompile/r-compiling/local/local320/lib/x64 -Ld:/RCompile/r-compiling/local/local320/lib -lgfortran -LC:/Users/pantera/DOCUME~1/R/R-32~1.2/bin/x64 -lR
  installing to C:/Users/pantera/AppData/Local/Temp/RtmpQdJJko/devtools_install_1df837dd6c29/myPack/libs/x64
  * DONE (myPack)
  First time using roxygen2. Upgrading automatically...
  Updating roxygen version in  C:\panterasBox\myPack/DESCRIPTION 
  Writing NAMESPACE
  Writing myFunc.Rd
  &gt; install("myPack")
  Installing myPack
  "C:/Users/pantera/DOCUME~1/R/R-32~1.2/bin/x64/R" --no-site-file --no-environ --no-save --no-restore CMD INSTALL  \
  "C:/panterasBox/myPack" --library="C:/Users/pantera/Documents/R/R-3.2.2/library" --install-tests 
  
  * installing *source* package 'myPack' ...
  ** libs
  
  *** arch - i386
  make: Nothing to be done for `all'.
  installing to C:/Users/pantera/Documents/R/R-3.2.2/library/myPack/libs/i386
  
  *** arch - x64
  make: Nothing to be done for `all'.
  installing to C:/Users/pantera/Documents/R/R-3.2.2/library/myPack/libs/x64
  ** R
  ** preparing package for lazy loading
  ** help
  *** installing help indices
  ** building package indices
  ** testing if installed package can be loaded
  *** arch - i386
  Error in inDL(x, as.logical(local), as.logical(now), ...) : 
    unable to load shared object 'C:/Users/pantera/Documents/R/R-3.2.2/library/myPack/libs/i386/mypack.dll':
    LoadLibrary failure:  %1 is not a valid Win32 application.
  
  Error: loading failed
  Execution halted
  *** arch - x64
  ERROR: loading failed for 'i386'
  * removing 'C:/Users/pantera/Documents/R/R-3.2.2/library/myPack'
  Error: Command failed (1)
  </code></pre>
  
  <p>I have also tried to build and check the package via the command line using <code>R CMD build myPack</code> and then <code>R CMD check myPack_*tar.gz</code>. The only error I get doing that is something about my LaTeX package.</p>
  
  <p>Thank you for reading this, and I appreciate any help offered.</p>
  
  <p>Disclaimer: I did ask this question previously, but I wanted to ask again in a "minimal fashion".</p>