data type size in c

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data type size in c
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used in gcc compiler
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• A char (one byte) will be 1-byte aligned.
• A short (two bytes) will be 2-byte aligned.
• An int (four bytes) will be 4-byte aligned.
• A long (four bytes) will be 4-byte aligned.
• A float (four bytes) will be 4-byte aligned.
• A double (eight bytes) will be 8-byte aligned on Windows and 4-byte aligned on Linux (8-byte with -malign-double compile time option).
• A long long (eight bytes) will be 8-byte aligned.
• A long double (ten bytes with C++Builder and DMC, eight bytes with Visual C++, twelve bytes with GCC) will be 8-byte aligned with C++Builder, 2-byte aligned with DMC, 8-byte aligned with Visual C++ and 4-byte aligned with GCC.
• Any pointer (four bytes) will be 4-byte aligned. (e.g.: char*, int*)

• The only notable differences in alignment for an LP64 64-bit system when compared to a 32-bit system are:
• A long (eight bytes) will be 8-byte aligned.
• A double (eight bytes) will be 8-byte aligned.
• A long double (eight bytes with Visual C++, sixteen bytes with GCC) will be 8-byte aligned with Visual C++ and 16-byte aligned with GCC.
• Any pointer (eight bytes) will be 8-byte aligned.