= Common issues with GCC-4.6 / G++-4.6 =

GCC-4.6 is again more strict, introduces new warnings, and lets packages fail to build, which did succeed to build with earlier GCC versions.

== Warnings ==

=== Warning format ===

Every warning has the option which did produce the warning appended to the warnings, e.g.

{{{
FAILURE: warning diffs:  1c1
< #warning undefining SECOND due to option name conflict [-Wcpp]
---
> #warning undefining SECOND due to option name conflict
FAIL: cond.test
}}}

=== New warning -Wunused-but-set-variable ===

This triggers a lot:

{{{
uuid_gen_unix.c:62:20: error: variable 'tv' set but not used [-Werror=unused-but-set-variable]
}}}

Either fix it, or if the package is built with -Werror, add as a workaround: -Wno-error=unused-but-set-variable

== C++ ==

=== NULL not defined ===

{{{
../build/include/apt-pkg/weakptr.h:58:26: error: 'NULL' was not declared in this scope
}}}

Fix: #include <cstdlib> is missing.

=== ptrdiff_t does not name a type ===

{{{
/usr/include/sigc++-2.0/sigc++/signal.h:38:11: error: 'ptrdiff_t' does not name a type
}}}

Fix: #include [[http://www.cplusplus.com/reference/clibrary/cstddef/|<cstddef>]]

=== size_t does not name a type ===

djvulibre:
{{{
GSmartPointer.h:497:30: error: 'size_t' does not name a type
}}}

Fix: #include [[http://www.cplusplus.com/reference/clibrary/cstddef/|<cstddef>]]

== Linker ==

=== -z syms unknown ===

ld.gold doesn't know about -z syms.

d-conf:
{{{
  CCLD   libdconfsettings.so
gcc: error: unrecognized option '-avoid-version'
}}}

{{{
gcc kerneloops.o submit.o dmesg.o configfile.o -Wl,--as-needed `pkg-config --libs glib-2.0 dbus-glib-1` `curl-config --libs` -Wl,"-z relro" -Wl,"-z now"  -o kerneloops
/usr/bin/ld.gold:  relro: unknown -z option
/usr/bin/ld.gold: use the --help option for usage information
collect2: ld returned 1 exit status
}}}