9.63 __attribute__((packed)) variable attribute

The packed variable attribute specifies that a variable or structure field has the smallest possible alignment. That is, one byte for a variable, and one bit for a field, unless you specify a larger value with the aligned attribute.


This variable attribute is a GNU compiler extension that the ARM compiler supports.


    char a;
    int b __attribute__((packed));
} Variable_Attributes_packed_0;
Related concepts
4.34 The __packed qualifier and unaligned data access in C and C++ code
4.39 Comparisons of an unpacked struct, a __packed struct, and a struct with individually __packed fields, and of a __packed struct and a #pragma packed struct
Related reference
9.56 __attribute__((packed)) type attribute
9.91 #pragma pack(n)
9.12 __packed
10.4 Structures, unions, enumerations, and bitfields in ARM C and C++
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