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c++cgccgcc-warning

The difference between __attribute__((unused)) and __attribute((unused)) in GCC

__attribute__((unused)) and __attribute((unused)) can mark variables as unused to avoid unused warning.

What is the difference between them？

Solution

  • In the GCC repository, in the file c-common.c, the array c_common_reswords of the type struct c_common_resword is defined.

    In the array, you will find the following elements: 

     { "__attribute",   RID_ATTRIBUTE,  0 },
 { "__attribute__", RID_ATTRIBUTE,  0 },

    And RID_ATTRIBUTE is defined in c-common.h in the enum rid in the /* C extensions */ section.

    So __attribute and __attribute__ are the same.