<html>
    <head>
      <base href="https://bugs.llvm.org/">
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - clang errors out if .h file is specified as an input along with .c/.cpp"
   href="https://bugs.llvm.org/show_bug.cgi?id=33533">33533</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>clang errors out if .h file is specified as an input along with .c/.cpp
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>clang
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>enhancement
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>Driver
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>manojgupta@google.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>george.burgess.iv@gmail.com, llozano@chromium.org, llvm-bugs@lists.llvm.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>$ cat test.c
int foo()
{
    return 0;
}

$ cat test.h
#include <stdlib.h>

$ clang -fpic -std=gnu99 -Wall -Werror -pedantic -Wall -g -o libtemp.so -shared
-Wl,-soname,libtemp.so test.c test.h

clang-5.0: error: cannot specify -o when generating multiple output files

This works with GCC however.

$ gcc -fpic -std=gnu99 -Wall -Werror -pedantic -Wall -g -o libtemp.so -shared
-Wl,-soname,libtemp.so test.c test.h   => Produces libtemp.so

Interestingly, clang does understand that this is a header file and tries to
compiler it to a pch file.

 "/usr/bin/clang-5.0" "-cc1" "-triple" "x86_64-pc-linux-gnu" "-emit-pch"
"-disable-free" "-disable-llvm-verifier" "-discard-value-names"
"-main-file-name" "d.h" "-mrelocation-model" "pic" "-pic-level" "1"
"-mthread-model" "posix" "-mdisable-fp-elim" "-fmath-errno" "-masm-verbose"
"-mconstructor-aliases" "-munwind-tables" "-fuse-init-array" "-target-cpu"
"x86-64" "-dwarf-column-info" "-debug-info-kind=limited" "-dwarf-version=4"
"-debugger-tuning=gdb" "-resource-dir" "/usr/lib64/clang/5.0.0"
"-internal-isystem" "/usr/local/include" "-internal-isystem"
"/usr/lib64/clang/5.0.0/include" "-internal-externc-isystem" "/include"
"-internal-externc-isystem" "/usr/include" "-Wall" "-Werror" "-Wall"
"-pedantic" "-std=gnu99" "-fdebug-compilation-dir" "/tmp" "-ferror-limit" "19"
"-fmessage-length" "140" "-fobjc-runtime=gcc" "-fdiagnostics-show-option"
"-fcolor-diagnostics" "-o" "libtemp.so" "-x" "c-header" "d.h"

So this is most likely an unhandled case in the lib/Driver/Driver.cpp

void Driver::BuildJobs(Compilation &C) const {

  // It is an error to provide a -o option if we are making multiple output
  // files.
  if (FinalOutput) {
    unsigned NumOutputs = 0;
    for (const Action *A : C.getActions())
      if (A->getType() != types::TY_Nothing) // =>  Should handle header
compilations here .
        ++NumOutputs;

    if (NumOutputs > 1) {
      Diag(clang::diag::err_drv_output_argument_with_multiple_files);
      FinalOutput = nullptr;
    }
  }</pre>
        </div>
      </p>


      <hr>
      <span>You are receiving this mail because:</span>

      <ul>
          <li>You are on the CC list for the bug.</li>
      </ul>
    </body>
</html>