avoid casting away const in a couple of silly places #22300
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Noticed this while reviewing Perl#22271. If you build with: ./Configure -des -Dusedevel -Ud_strnlen -Accflags=-Wcast-qual -Dcc=g++ you will see amongst many other warnings: inline.h: In function ‘size_t Perl_my_strnlen(const char*, size_t)’: inline.h:4220:23: warning: cast from type ‘const void*’ to type ‘char*’ casts away qualifiers [-Wcast-qual] 4220 | const char *end = (char *) memchr(str, '\0', maxlen); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The cast itself is only needed on C++ to cast from "const void *", C doesn't require any cast here.
Seen with:
./Configure -des -Dusedevel -Accflags=-Wcast-qual
mathoms.c: In function ‘Perl_utf8_to_uvchr’:
utf8.h:804:53: warning: cast discards ‘const’ qualifier from pointer target type
[-Wcast-qual]
804 | (UNLIKELY(s[0] == '\0') ? 1 : my_strnlen((char *) (s), UTF8SK
IP(s)))
| ^
embed.h:792:87: note: in definition of macro ‘utf8_to_uvchr_buf_helper’
792 | # define utf8_to_uvchr_buf_helper(a,b,c) Perl_utf8_to_uvchr_buf_h
elper(aTHX_ a,b,c)
|
^
mathoms.c:970:12: note: in expansion of macro ‘utf8_to_uvchr_buf’
970 | return utf8_to_uvchr_buf(s, s + UTF8_CHK_SKIP(s), retlen);
| ^~~~~~~~~~~~~~~~~
mathoms.c:970:37: note: in expansion of macro ‘UTF8_CHK_SKIP’
970 | return utf8_to_uvchr_buf(s, s + UTF8_CHK_SKIP(s), retlen);
| ^~~~~~~~~~~~~
mathoms.c seems to be the only user of this macro.
This came up when reviewing Perl#22271
khwilliamson
approved these changes
Jun 18, 2024
khwilliamson
approved these changes
Jun 18, 2024
Leont
approved these changes
Jun 18, 2024
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See the commit messages for how to reproduce the cast-qual warnings.