https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99868
Bug ID: 99868
Summary: std::string is not copied correctly
Product: gcc
Version: 7.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: apyszczuk at gmail dot com
Target Milestone: ---
Created attachment 50495
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50495&action=edit
save-temps
This code does not correctly copy the string *str*.
#include <iostream>
#include <string>
void mod (char* data) {
data[0] = 'c';
}
int main () {
const std::string str {"8:0.0"};
std::string dn {str};
mod (const_cast<char*> (dn.data ()));
std::cout << "dn = " << dn << "\n";
std::cout << "str = " << str << "\n";
return 0;
}
*dn* should be "c:0.0" and *str* should be untouched but in fact both have the
same value.
If I change:
std::string dn {str};
to:
std::string dn {str.c_str ()};
then *str* is "8:0.0" as it should be.
VERSION:
--
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/opt/rh/devtoolset-7/root/usr/libexec/gcc/x86_64-redhat-linux/7/lto-wrapper
Target: x86_64-redhat-linux
Configured with: ../configure --enable-bootstrap
--enable-languages=c,c++,fortran,lto --prefix=/opt/rh/devtoolset-7/root/usr
--mandir=/opt/rh/devtoolset-7/root/usr/share/man
--infodir=/opt/rh/devtoolset-7/root/usr/share/info
--with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-shared
--enable-threads=posix --enable-checking=release --enable-multilib
--with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions
--enable-gnu-unique-object --enable-linker-build-id
--with-gcc-major-version-only --enable-plugin --with-linker-hash-style=gnu
--enable-initfini-array --with-default-libstdcxx-abi=gcc4-compatible
--with-isl=/builddir/build/BUILD/gcc-7.2.1-20170829/obj-x86_64-redhat-linux/isl-install
--enable-libmpx --enable-gnu-indirect-function --with-tune=generic
--with-arch_32=i686 --build=x86_64-redhat-linux
Thread model: posix
gcc version 7.2.1 20170829 (Red Hat 7.2.1-1) (GCC)
--
COMPILATION:
g++ -std=c++17 main.cpp -o main && ./main
(in 11 and 14 is the same)
As I saw, GCC 8.3 does not have the same issue: https://ideone.com/EuNi6U
