https://issues.dlang.org/show_bug.cgi?id=24297

          Issue ID: 24297
           Summary: ImportC incompatible with glibc _FORTIFY_SOURCE
           Product: D
           Version: D2
          Hardware: All
                OS: Linux
            Status: NEW
          Keywords: ImportC
          Severity: enhancement
          Priority: P5
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: dlang-bugzilla@thecybershadow.net

$ echo '#include <stdio.h>' > test.c && dmd -P=-D_FORTIFY_SOURCE -P=-O test.c
/usr/include/bits/stdio2.h(198): Error: found `0` when expecting `)`
/usr/include/bits/stdio2.h(198): Error: found `)` instead of statement
/usr/include/bits/stdio2.h(200): Error: found `0` when expecting `)`
/usr/include/bits/stdio2.h(200): Error: found `)` instead of statement
/usr/include/bits/stdio2.h(210): Error: found `0` when expecting `)`
/usr/include/bits/stdio2.h(210): Error: found `)` instead of statement
/usr/include/bits/stdio2.h(212): Error: found `0` when expecting `)`
/usr/include/bits/stdio2.h(212): Error: found `)` instead of statement
/usr/include/bits/stdio2.h(237): Error: found `0` when expecting `)`
/usr/include/bits/stdio2.h(237): Error: found `)` instead of statement
/usr/include/bits/stdio2.h(260): Error: no type for declarator before `return`
/usr/include/bits/stdio2.h(261): Error: no type for declarator before `}`
/usr/include/bits/stdio2.h(262): Error: no type for declarator before `if`
/usr/include/bits/stdio2.h(264): Error: no type for declarator before `return`
/usr/include/bits/stdio2.h(266): Error: no type for declarator before `}`

Relevant part of the file:

   194  __fortify_function __wur __fortified_attr_access (__write_only__, 1, 2)
char *
   195  fgets (char *__restrict __s, int __n, FILE *__restrict __stream)
   196  {
   197    size_t sz = __glibc_objsize (__s);
   198    if (__glibc_safe_or_unknown_len (__n, sizeof (char), sz))
   199      return __fgets_alias (__s, __n, __stream);
   200    if (__glibc_unsafe_len (__n, sizeof (char), sz))
   201      return __fgets_chk_warn (__s, sz, __n, __stream);
   202    return __fgets_chk (__s, sz, __n, __stream);
   203  }


Nix enables these flags automatically for its wrapped C preprocessor. It is enabled by default but can be disabled.

Not sure if this is something that's at all reasonable to implement in ImportC or not.

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