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Home > Compiler-specific Features > Instruction intrinsics > __builtin_constant_p |
This builtin function determines if a value is known to be constant at compile-time.
This builtin function is a GNU compiler extension that is supported by the ARM compiler.
__builtin_constant_p
returns the integer
1 if the argument is known to be a compile-time constant and 0 if
it is not known to be a compile-time constant.
A return value of 0 does not indicate that the value is not
a constant, but that the compiler cannot prove it is a constant
with the specified value of the -O
option.