Don't rely on unsequenced evaluation order in bintool/metadata.h (#187) #188
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…pberrypi#187) With the following compiler: % /Library/Developer/CommandLineTools/usr/bin/c++ --version Apple clang version 15.0.0 (clang-1500.3.9.4) Target: arm64-apple-darwin23.6.0 Thread model: posix InstalledDir: /Library/Developer/CommandLineTools/usr/bin I was getting the following warning: metadata.h:258:44: warning: multiple unsequenced modifications to 'i' [-Wunsequenced] It appears as though the code relies on the leftmost i++ happening first, followed by the rightmost, but the language seemingly provides no such guarantee. Fix this by reading the low and high words in order, then combining them, rather than doing so in a single expression.
lurch
reviewed
Dec 8, 2024
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Oh, and can you change the base branch to |
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With the following compiler:
% /Library/Developer/CommandLineTools/usr/bin/c++ --version Apple clang version 15.0.0 (clang-1500.3.9.4)
Target: arm64-apple-darwin23.6.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin
I was getting the following warning:
metadata.h:258:44: warning: multiple unsequenced modifications to 'i' [-Wunsequenced]
It appears as though the code relies on the leftmost i++ happening first, followed by the rightmost, but the language seemingly provides no such guarantee.
Fix this by reading the low and high words in order, then combining them, rather than doing so in a single expression.