Reducing Warnings - Compile with C99 on Evergreen by default #1067
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| @@ -28,6 +29,7 @@ set -o errexit # Exit the script with error if any of the commands fail | |||
| # ZSTD Build against system zstd. | |||
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| # Options for this script. | |||
| C_STD_VERSION=${CSTD_VERSION:-99} | |||
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+1 for a dedicated env var
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If you have not already, I suggest running a full patch build to check compile tasks on all platforms. |
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@kevinAlbs Latest patch builds are noisy due to unrelated server compat issues, but compile tasks were verified here: https://spruce.mongodb.com/version/62cc9a6557e85a7ecf6b16f2/tasks |
| @@ -28,6 +29,7 @@ set -o errexit # Exit the script with error if any of the commands fail | |||
| # ZSTD Build against system zstd. | |||
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| # Options for this script. | |||
| C_STD_VERSION=${CSTD_VERSION:-99} | |||
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@eramongodb: I think this was a typo, but it appears to have been fixed in a subsequent commit: f4a83c0#diff-5621bd7804f10985a5f14a01ee66b14439494aa0a6cdfa6c6debd151e7c90d7aR10
Likewise for compile-windows.sh.
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Correct. This mistake was in part what motivated the addition of the check_var_opt/check_var_req functions in the referenced commit.
Description
This PR is a followup to #920 and is related to CDRIVER-4136.
This PR ensures that all builds of the C Driver on Evergreen are able to be compiled with
-std=c99(or equivalent) by default to ensure strict conformance with the C99 standard across all platforms and configurations. This addresses all C89/C90 compatibility related warnings emitted due to use of C99 features.In the spirit of minimizing platform-specific configuration flags, the C standard is specified via CMake's
CMAKE_C_STANDARDandCMAKE_C_STANDARD_REQUIREDon both Linux and Windows.CMAKE_C_EXTENSIONSis set toOFFto ensure strict C99 conformance and that any extensions being depended on are explicitly opted into.Setting
CMAKE_C_EXTENSIONStoOFFexposed a configuration bug on RHEL 6.2 and RHEL 7.0, which provides glibc versions 2.12 and 2.17 respectively. #920 proposed removing_BSD_SOURCEin favor of_DEFAULT_SOURCEdue to the former being deprecated; however,_DEFAULT_SOURCEis only supported given glibc version 2.19 and newer. To support glibc version 2.19 and earlier while also supporting strict C99 conformance, this PR partially reverts the changes in #920.Therefore, the full set of compile definitions to explicitly opt into POSIX features and non-standard extensions currently being used by the C driver include:
_XOPEN_SOURCE=700: required to enable use ofstrnlen(>=700) in addition to other features in the X/Open namespace (i.e.pthread_rwlock_*(>=500)) as required by the POSIX specification._DEFAULT_SOURCE: required to enable use ofgetpagesize,h_errno, and other BSD-derived definitions._BSD_SOURCE: required for compatibility with glibc 2.19 and earlier._DARWIN_C_SOURCE: required to enable use of_SC_NPROCESSORS_ONLNand other non-POSIX extensions on MacOS that are otherwise disabled by_POSIX_C_SOURCE(set to200112Lby_XOPEN_SOURCE=700)._BSD_SOURCEcould be removed once all platforms with glibc version 2.19 or earlier are no longer supported.The
debug-compile-c99task is removed due to redundancy.