Ring buffer usage & whether the operation has BUG?

1. Use ring buffers to exchange data, threadWrite-> buf-> threadRead
threadWrite {

memcpy(buf[pushCount & mask], value, size);
pushCountPP;
...

}

threadRead {

...

}

if mask = = 2, pushCount accumulates from 0
when pushCount = 0
pushCount & mask = = 0
when pushCount = 1
pushCount & mask = = 0
when pushCount = 2
pushCount & mask = = 2

is there a problem? the second position of the array is not written, and the first position is written twice

.

2. Is there any special requirement for the mask mask of the ring queue, such as parity and so on? please answer

.
Mar.21,2021

if you use & , the mask mask must satisfy $2 ^ n-1 $$

The

ring buffer actually uses a residual operation to ensure that it does not explode. If you use the normal balance % , then there is no requirement for mask. If you use bitwise and & , only if mask satisfies the above conditions, all binary bits are 1 , which can be equivalent to the remainder.

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MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b2bb87-2ba9e.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b2bb87-2ba9e.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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