Install gcc-15.1 form source in Ubuntu (chatGpt reply)

✅ Step-by-step: Build and Install GCC 15.1 on Ubuntu

⚠️ Estimated time: ~30–60 mins
✅ Works on Ubuntu 20.04 / 22.04 / 24.04

---

1. Install dependencies

bash
sudo apt update
sudo apt install -y build-essential wget curl git \
  libgmp-dev libmpfr-dev libmpc-dev libisl-dev \
  flex bison libzstd-dev

2. Download GCC 15.1 source
bash
cd ~/Downloads
wget https://ftp.gnu.org/gnu/gcc/gcc-15.1.0/gcc-15.1.0.tar.xz
tar -xf gcc-15.1.0.tar.xz
cd gcc-15.1.0
./contrib/download_prerequisites


This will fetch GMP, MPFR, MPC, and ISL into the source tree.


3. Create build directory
bash
mkdir ../gcc-15.1-build
cd ../gcc-15.1-build


4. Configure build
bash
../gcc-15.1.0/configure \
  --prefix=/opt/gcc-15.1 \
  --disable-multilib \
  --enable-languages=c,c++,fortran \
  --enable-bootstrap \
  --enable-checking=release


5. Build (takes time)
bash
make -j$(nproc)


6. Install
bash
sudo make install

7. Use GCC 15.1
Add it to your shell:
bash
echo 'export PATH=/opt/gcc-15.1/bin:$PATH' >> ~/.bashrc
echo 'export LD_LIBRARY_PATH=/opt/gcc-15.1/lib64:$LD_LIBRARY_PATH' >> ~/.bashrc
source ~/.bashrc


8. Check version
bash
gcc --version

Should show:
scss
gcc (GCC) 15.1.0


✅ Optional: Set it system-wide (alternative)
Update update-alternatives if you want it globally:
bash
sudo update-alternatives --install /usr/bin/gcc gcc /opt/gcc-15.1/bin/gcc 1501
sudo update-alternatives --install /usr/bin/g++ g++ /opt/gcc-15.1/bin/g++ 1501

Then run:
bash
sudo update-alternatives --config gcc
sudo update-alternatives --config g++