Created attachment 36433 [details] Preprocessed File In general, they convert a char sequence representing a negative value to its complement, while it should be the maximum positive value which can be represented by unsigned long (or unsigned long long) by www.cplusplus.com Here is the code: #include <iostream> #include <climits> #include <cstdlib> using namespace std; int main() { cout << strtoul("-2", nullptr, 10) << endl; cout << ULONG_MAX << endl; cout << strtoull("-2", nullptr, 10) << endl; cout << ULLONG_MAX << endl; return 0; } and the output is: 4294967294 4294967295 18446744073709551614 18446744073709551615 I use the IDE CodeBlocks to help compile the source file. The following is the build log. Using built-in specs. COLLECT_GCC=g++.exe Target: x86_64-w64-mingw32 Configured with: ../../../src/gcc-5.2.0/configure --host=x86_64-w64-mingw32 --build=x86_64-w64-mingw32 --target=x86_64-w64-mingw32 --prefix=/mingw64 --with-sysroot=/c/mingw520/x86_64-520-posix-seh-rt_v4-rev0/mingw64 --with-gxx-include-dir=/mingw64/x86_64-w64-mingw32/include/c++ --enable-shared --enable-static --disable-multilib --enable-languages=c,c++,fortran,objc,obj-c++,lto --enable-libstdcxx-time=yes --enable-threads=posix --enable-libgomp --enable-libatomic --enable-lto --enable-graphite --enable-checking=release --enable-fully-dynamic-string --enable-version-specific-runtime-libs --disable-isl-version-check --disable-libstdcxx-pch --disable-libstdcxx-debug --enable-bootstrap --disable-rpath --disable-win32-registry --disable-nls --disable-werror --disable-symvers --with-gnu-as --with-gnu-ld --with-arch=nocona --with-tune=core2 --with-libiconv --with-system-zlib --with-gmp=/c/mingw520/prerequisites/x86_64-w64-mingw32-static --with-mpfr=/c/mingw520/prerequisites/x86_64-w64-mingw32-static --with-mpc=/c/mingw520/prerequisites/x86_64-w64-mingw32-static --with-isl=/c/mingw520/prerequisites/x86_64-w64-mingw32-static --with-pkgversion='x86_64-posix-seh-rev0, Built by MinGW-W64 project' --with-bugurl=http://sourceforge.net/projects/mingw-w64 CFLAGS='-O2 -pipe -I/c/mingw520/x86_64-520-posix-seh-rt_v4-rev0/mingw64/opt/include -I/c/mingw520/prerequisites/x86_64-zlib-static/include -I/c/mingw520/prerequisites/x86_64-w64-mingw32-static/include' CXXFLAGS='-O2 -pipe -I/c/mingw520/x86_64-520-posix-seh-rt_v4-rev0/mingw64/opt/include -I/c/mingw520/prerequisites/x86_64-zlib-static/include -I/c/mingw520/prerequisites/x86_64-w64-mingw32-static/include' CPPFLAGS= LDFLAGS='-pipe -L/c/mingw520/x86_64-520-posix-seh-rt_v4-rev0/mingw64/opt/lib -L/c/mingw520/prerequisites/x86_64-zlib-static/lib -L/c/mingw520/prerequisites/x86_64-w64-mingw32-static/lib ' Thread model: posix gcc version 5.2.0 (x86_64-posix-seh-rev0, Built by MinGW-W64 project) COLLECT_GCC_OPTIONS='-Wall' '-fexceptions' '-v' '-save-temps' '-O2' '-std=c++14' '-c' '-o' 'obj\Release\main.o' '-shared-libgcc' '-mtune=core2' '-march=nocona' D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../libexec/gcc/x86_64-w64-mingw32/5.2.0/cc1plus.exe -E -quiet -v -iprefix D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/5.2.0/ -D_REENTRANT D:\C++Program\test\main.cpp -mtune=core2 -march=nocona -std=c++14 -Wall -fexceptions -O2 -fpch-preprocess -o main.ii ignoring duplicate directory "D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/5.2.0/include" ignoring nonexistent directory "C:/mingw520/x86_64-520-posix-seh-rt_v4-rev0/mingw64C:/msys64/mingw64/lib/gcc/x86_64-w64-mingw32/5.2.0/../../../../include" ignoring duplicate directory "D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/5.2.0/include-fixed" ignoring duplicate directory "D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/5.2.0/../../../../x86_64-w64-mingw32/include" ignoring nonexistent directory "C:/mingw520/x86_64-520-posix-seh-rt_v4-rev0/mingw64/mingw/include" #include "..." search starts here: #include <...> search starts here: D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/5.2.0/include D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/5.2.0/include-fixed D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/5.2.0/../../../../x86_64-w64-mingw32/include D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/lib/gcc/../../x86_64-w64-mingw32/include/c++ D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/lib/gcc/../../x86_64-w64-mingw32/include/c++/x86_64-w64-mingw32 D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/lib/gcc/../../x86_64-w64-mingw32/include/c++/backward End of search list. COLLECT_GCC_OPTIONS='-Wall' '-fexceptions' '-v' '-save-temps' '-O2' '-std=c++14' '-c' '-o' 'obj\Release\main.o' '-shared-libgcc' '-mtune=core2' '-march=nocona' D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../libexec/gcc/x86_64-w64-mingw32/5.2.0/cc1plus.exe -fpreprocessed main.ii -quiet -dumpbase main.cpp -mtune=core2 -march=nocona -auxbase-strip obj\Release\main.o -O2 -Wall -std=c++14 -version -fexceptions -o main.s GNU C++14 (x86_64-posix-seh-rev0, Built by MinGW-W64 project) version 5.2.0 (x86_64-w64-mingw32) compiled by GNU C version 5.2.0, GMP version 6.0.0, MPFR version 3.1.3, MPC version 1.0.3 GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 GNU C++14 (x86_64-posix-seh-rev0, Built by MinGW-W64 project) version 5.2.0 (x86_64-w64-mingw32) compiled by GNU C version 5.2.0, GMP version 6.0.0, MPFR version 3.1.3, MPC version 1.0.3 GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072 Compiler executable checksum: 21af4d84309555a285c9e50ab0605aa1 COLLECT_GCC_OPTIONS='-Wall' '-fexceptions' '-v' '-save-temps' '-O2' '-std=c++14' '-c' '-o' 'obj\Release\main.o' '-shared-libgcc' '-mtune=core2' '-march=nocona' D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/5.2.0/../../../../x86_64-w64-mingw32/bin/as.exe -v -o obj\Release\main.o main.s GNU assembler version 2.25 (x86_64-w64-mingw32) using BFD version (GNU Binutils) 2.25 COMPILER_PATH=D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../libexec/gcc/x86_64-w64-mingw32/5.2.0/;D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../libexec/gcc/;D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/5.2.0/../../../../x86_64-w64-mingw32/bin/ LIBRARY_PATH=D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/5.2.0/;D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../lib/gcc/;D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/5.2.0/../../../../x86_64-w64-mingw32/lib/../lib/;D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/5.2.0/../../../../lib/;D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/5.2.0/../../../../x86_64-w64-mingw32/lib/;D:/mingw-w64/x86_64-5.2.0-posix-seh-rt_v4-rev0/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/5.2.0/../../../ COLLECT_GCC_OPTIONS='-Wall' '-fexceptions' '-v' '-save-temps' '-O2' '-std=c++14' '-c' '-o' 'obj\Release\main.o' '-shared-libgcc' '-mtune=core2' '-march=nocona' g++.exe -o bin\Release\test.exe obj\Release\main.o -s Output file is bin\Release\test.exe with size 18.50 KB Process terminated with status 0 (0 minute(s), 0 second(s)) 0 error(s), 0 warning(s) (0 minute(s), 0 second(s))
If you look in <cstdlib> you will see these functions are not provided by GCC's header, they come from your C library, so this is nothing to do with GCC. In any case, cplusplus.com is wrong, the functions behave as required by the C standard: If the subject sequence begins with a minus sign, the value resulting from the conversion is negated (in the return type).
(In reply to Jonathan Wakely from comment #1) > If you look in <cstdlib> you will see these functions are not provided by > GCC's header, they come from your C library, so this is nothing to do with > GCC. > > In any case, cplusplus.com is wrong, the functions behave as required by the > C standard: > > If the subject sequence begins with a minus sign, the value resulting from > the conversion is negated (in the return type). But the C standard also says "If the correct value is outside the range of representable values, LONG_MIN, LONG_MAX, LLONG_MIN, LLONG_MAX, ULONG_MAX, or ULLONG_MAX is returned (according to the return type and sign of the value, if any)".
(In reply to Jonathan Wakely from comment #1) > If you look in <cstdlib> you will see these functions are not provided by > GCC's header, they come from your C library, so this is nothing to do with > GCC. Again, those functions have nothing to do with GCC.
(In reply to Jonathan Wakely from comment #3) > (In reply to Jonathan Wakely from comment #1) > > If you look in <cstdlib> you will see these functions are not provided by > > GCC's header, they come from your C library, so this is nothing to do with > > GCC. > > Again, those functions have nothing to do with GCC. Thanks, I see it. I just want to confirm that such implementation conflicts with the C standard.
(In reply to 8826055 from comment #4) For POSIX, see http://austingroupbugs.net/view.php?id=700 For GLIBC see http://www.gnu.org/software/libc/manual/html_node/Parsing-of-Integers.html