https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112347
--- Comment #13 from David Binderman <dcb314 at hotmail dot com> --- I have been trying to get this C++ code to produce the new warning: #include <cstdlib> struct S { int a[ 10]; float * b[ 20]; }; extern void g( S * ps); void f( int n) { S * ps = (S *) calloc( sizeof( S), 1); g( ps); S * ps2 = (S *) calloc( 1, sizeof( S)); g( ps2); S * ps3 = (S *) calloc( 1, sizeof( S) / 2); g( ps3); } $ ~/gcc/results/bin/g++ -g -O2 -Wall -Wextra -Walloc-size -c nov2b.cc cc1plus: warning: command-line option ‘-Walloc-size’ is valid for C/ObjC but not for C++ nov2b.cc: In function ‘void f(int)’: nov2b.cc:12:13: warning: unused parameter ‘n’ [-Wunused-parameter] 12 | void f( int n) | ~~~~^ $ ~/gcc/results/bin/g++ -v Using built-in specs. COLLECT_GCC=/home/dcb38/gcc/results/bin/g++ COLLECT_LTO_WRAPPER=/home/dcb38/gcc/results.20231102.asan.ubsan/libexec/gcc/x86_64-pc-linux-gnu/14.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../trunk.year/configure --prefix=/home/dcb38/gcc/results.20231102.asan.ubsan --disable-multilib --disable-bootstrap --with-build-config=bootstrap-asan --with-build-config=bootstrap-ubsan --with-pkgversion=01c18f58d37865d5 --enable-checking=df,extra,fold,rtl,yes --enable-languages=c,c++,fortran Thread model: posix Supported LTO compression algorithms: zlib zstd gcc version 14.0.0 20231102 (experimental) (01c18f58d37865d5) $ I think calloc is available in C++, so the warning is wrong.