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