<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 - Enhancement request: __attribute__((warn_untested_result))"
   href="https://bugs.llvm.org/show_bug.cgi?id=33240">33240</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Enhancement request: __attribute__((warn_untested_result))
          </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>-New Bugs
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>joe@perches.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Duplicate request submitted to gcc

<a href="https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80522">https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80522</a>

A possibly useful addition similar to:

__attribute__((warn_unused_result))

might be

__attribute__((warn_untested_result))

for things like allocation failures that
are not verified before use.

For instance:

    void *malloc(size_t size);

could become

    void * __attribute__((warn_untested_result)) malloc(size_t size)

so that

    #include <stdlib.h>

    struct foo {
            int bar;
    };

    struct foo *alloc_foo(void)
    {
            struct foo *baz = malloc(sizeof(struct foo));
            baz->bar = 1;
            return baz;
    }

The compiler could emit a warning on the set
of baz->bar as an intermediate test of baz
is not performed before any use of baz.

    struct foo *alloc_foo(void)
    {
            struct foo *baz = malloc(sizeof(struct foo));
            if (baz) baz->bar = 1;
            return baz;
    }

This variant would not emit a warning.

Similarly, alloc_foo could use that new attribute.

Martin Sebor also mentioned that non-allocation
functions like fopen could also use this __attribute__
mechanism.</pre>
        </div>
      </p>


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