Re: [gentoo-user] Strange GCC behavior

[Michael Mol]

On Thu, Sep 29, 2011 at 1:27 PM, Nilesh Govindarajan
<contact@××××××××.com> wrote:
> Default function arguments in C are specified like this:
>
> int func(int a = 10) {} // just a dummy function
>
> Now I save that in a file called foo.c
>
> The above piece of code is valid in C as well as C++
>
> Now see this:
>
> nilesh@Linux ~ $ cat /tmp/foo.c
> int func(int a = 1) {}
> nilesh@Linux ~ $ gcc /tmp/foo.c
> /tmp/foo.c:1:16: error: expected ‘;’, ‘,’ or ‘)’ before ‘=’ token
> nilesh@Linux ~ $ g++ /tmp/foo.c
> /usr/lib/gcc/x86_64-pc-linux-gnu/4.5.3/../../../../lib64/crt1.o: In
> function `_start':
> (.text+0x20): undefined reference to `main'
> collect2: ld returned 1 exit status
> nilesh@Linux ~ $ gcc -v
> Using built-in specs.
> COLLECT_GCC=/usr/x86_64-pc-linux-gnu/gcc-bin/4.5.3/gcc
> COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.5.3/lto-wrapper
> Target: x86_64-pc-linux-gnu
> Configured with:
> /media/500GB/gentoo_portage/tmp/portage/sys-devel/gcc-4.5.3-r1/work/gcc-4.5.3/configure
> --prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.5.3
> --includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.5.3/include
> --datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.5.3
> --mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.5.3/man
> --infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.5.3/info
> --with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.5.3/include/g++-v4
> --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --disable-altivec
> --disable-fixed-point --without-ppl --without-cloog --disable-lto
> --enable-nls --without-included-gettext --with-system-zlib
> --disable-werror --enable-secureplt --enable-multilib
> --enable-libmudflap --disable-libssp --enable-libgomp --enable-cld
> --with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.5.3/python
> --enable-checking=release --disable-libgcj
> --enable-languages=c,c++,fortran --enable-shared --enable-threads=posix
> --enable-__cxa_atexit --enable-clocale=gnu
> --with-bugurl=http://bugs.gentoo.org/ --with-pkgversion='Gentoo 4.5.3-r1
> p1.0, pie-0.4.5'
> Thread model: posix
> gcc version 4.5.3 (Gentoo 4.5.3-r1 p1.0, pie-0.4.5)
> nilesh@Linux ~ $ g++ -v
> Using built-in specs.
> COLLECT_GCC=/usr/x86_64-pc-linux-gnu/gcc-bin/4.5.3/g++
> COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.5.3/lto-wrapper
> Target: x86_64-pc-linux-gnu
> Configured with:
> /media/500GB/gentoo_portage/tmp/portage/sys-devel/gcc-4.5.3-r1/work/gcc-4.5.3/configure
> --prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.5.3
> --includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.5.3/include
> --datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.5.3
> --mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.5.3/man
> --infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.5.3/info
> --with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.5.3/include/g++-v4
> --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --disable-altivec
> --disable-fixed-point --without-ppl --without-cloog --disable-lto
> --enable-nls --without-included-gettext --with-system-zlib
> --disable-werror --enable-secureplt --enable-multilib
> --enable-libmudflap --disable-libssp --enable-libgomp --enable-cld
> --with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.5.3/python
> --enable-checking=release --disable-libgcj
> --enable-languages=c,c++,fortran --enable-shared --enable-threads=posix
> --enable-__cxa_atexit --enable-clocale=gnu
> --with-bugurl=http://bugs.gentoo.org/ --with-pkgversion='Gentoo 4.5.3-r1
> p1.0, pie-0.4.5'
> Thread model: posix
> gcc version 4.5.3 (Gentoo 4.5.3-r1 p1.0, pie-0.4.5)
>
> Why is this happening? O_o

First guess, you need an int main() function, or you need to tell gcc
not to look for one.


-- 
:wq