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22 lines
743 B
C
22 lines
743 B
C
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#ifndef COSMOPOLITAN_LIBC_INTRIN_ONCE_H_
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#define COSMOPOLITAN_LIBC_INTRIN_ONCE_H_
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#include "libc/intrin/spinlock.h"
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#define _once(x) \
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({ \
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typeof(x) oncerc; \
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static bool once; \
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static typeof(oncerc) onceresult; \
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_Alignas(64) static char oncelock; \
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_spinlock(&oncelock); \
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if (once) { \
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oncerc = onceresult; \
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} else { \
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oncerc = onceresult = x; \
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} \
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_spunlock(&oncelock); \
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oncerc; \
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})
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#endif /* COSMOPOLITAN_LIBC_INTRIN_ONCE_H_ */
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