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author | Karl Williamson <public@khwilliamson.com> | 2011-09-24 11:29:09 -0600 |
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committer | Karl Williamson <public@khwilliamson.com> | 2011-10-01 09:58:08 -0600 |
commit | 3912bc886c99be4f8599922a1998dcf2cfffe877 (patch) | |
tree | 92dc953bad35ce426a7a8f96f24be2ee8796f816 /handy.h | |
parent | 94b42e47713770173606e6b7686a6ca5b74b41cc (diff) | |
download | perl-3912bc886c99be4f8599922a1998dcf2cfffe877.tar.gz |
handy.h: clarify, typos in comment
Diffstat (limited to 'handy.h')
-rw-r--r-- | handy.h | 19 |
1 files changed, 10 insertions, 9 deletions
@@ -562,15 +562,16 @@ patched there. The file as of this writing is cpan/Devel-PPPort/parts/inc/misc */ -/* FITS_IN_8_BITS(c) returns true if c occupies no more than 8 bits. It is - * designed to be hopefully bomb-proof, making sure that no bits of - * information are lost even on a 64-bit machine, but to get the compiler to - * optimize it out if possible. This is because Configure makes sure that the - * machine has an 8-bit byte, so if c is stored in a byte, the sizeof() - * guarantees that this evaluates to a constant true at compile time. The use - * of the mask instead of '< 256' keeps gcc from complaining that it is alway - * true, when c's storage class is a byte. Use U64TYPE because U64 is known - * only in the perl core, and this macro can be called from outside that */ +/* FITS_IN_8_BITS(c) returns true if c doesn't have a bit set other than in + * the lower 8. It is designed to be hopefully bomb-proof, making sure that no + * bits of information are lost even on a 64-bit machine, but to get the + * compiler to optimize it out if possible. This is because Configure makes + * sure that the machine has an 8-bit byte, so if c is stored in a byte, the + * sizeof() guarantees that this evaluates to a constant true at compile time. + * The use of the mask instead of '< 256' keeps gcc from complaining that it is + * always true, when c's storage class is a byte. Use U64TYPE because U64 is + * known only in the perl core, and this macro can be called from outside that + */ #ifdef HAS_QUAD # define FITS_IN_8_BITS(c) ((sizeof(c) == 1) || (((U64TYPE)(c) & 0xFF) == (U64TYPE)(c))) #else |