From ead3580db204703ec98434bb2ba2fd688a619e40 Mon Sep 17 00:00:00 2001 From: Andrew Clayton Date: Fri, 2 Dec 2022 17:20:37 +0000 Subject: Autodetect endianness. In configure we set NXT_HAVE_LITTLE_ENDIAN for i386, amd64 and x86_64. However that misses at least AArch64 (arm64) where it's usually run in little endian mode. However none of that really matters as NXT_HAVE_LITTLE_ENDIAN isn't used anywhere. So why this patch? The only place we need to explicitly know about endianness is the nxt_websocket_header_t structure where we lay it out differently depending on endianness. This is currently done using BYTE_ORDER, LITTLE_ENDIAN and BIG_ENDIAN macros. However on at least illumos (OpenSolaris / OpenIndiana) those macros are not defined and we get compiler errors due to duplicate structure members. So let's use our own NXT_HAVE_{BIG,LITTLE}_ENDIAN macros. However it would be better to detect endianness programmatically as some architectures can run in either mode, e.g Linux used to run in big endian on PowerPC but has since switched to little endian (to match x86). This commit adds an auto/endian script (using a slightly modified version of the test program from nginx's auto script), that checks for the endianness of the platform being built on. E.g checking for endianness ... little endian The next commit will switch the nxt_websocket_header_t structure over to these new macros. Link: Link: Tested-by: Alejandro Colomar Reviewed-by: Alejandro Colomar Signed-off-by: Andrew Clayton --- auto/endian | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 auto/endian (limited to 'auto') diff --git a/auto/endian b/auto/endian new file mode 100644 index 00000000..cb23639b --- /dev/null +++ b/auto/endian @@ -0,0 +1,31 @@ +# Copyright (C) Igor Sysoev +# Copyright (C) Andrew Clayton +# Copyright (C) Nginx, Inc. + + +nxt_feature="endianness" +nxt_feature_name= +nxt_feature_run=value +nxt_feature_incs= +nxt_feature_libs= +nxt_feature_test="#include + #include + + int main(void) { + int i = 0x11223344; + uint8_t *p; + + p = (uint8_t *)&i; + if (*p == 0x44) + printf(\"little endian\"); + else + printf(\"big endian\"); + return 0; + }" +. auto/feature + +if [ "$nxt_feature_value" = "little endian" ]; then + nxt_have=NXT_HAVE_LITTLE_ENDIAN . auto/have +else + nxt_have=NXT_HAVE_BIG_ENDIAN . auto/have +fi -- cgit