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`if (fpm_shm_size - size > 0)` will be rewritten by the compiler as this: `if (fpm_shm_size != size)`, which is undesirable. The reason this happens is that both variables are size_t, so subtracting them cannot be negative. The only way it can be not > 0, is if they're equal because the result will then be 0. This means that the else branch won't work properly. E.g. if `fpm_shm_size == 50` and `size == 51`, then `fpm_shm_size` will wraparound instead of becoming zero. To showcase that the compiler actually does this, take a look at this isolated case: https://godbolt.org/z/azobdWcrY. Here we can see the usage of the compare instruction + cmove, so the "then" branch is only done if the variables are equal. |
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| .. | ||
| fpm | ||
| tests | ||
| config.m4 | ||
| CREDITS | ||
| init.d.php-fpm.in | ||
| LICENSE | ||
| Makefile.frag | ||
| php-fpm.8.in | ||
| php-fpm.conf.in | ||
| php-fpm.service.in | ||
| status.html.in | ||
| www.conf.in | ||