libcpucycles

Prerequisites: `python3`; `gcc` and/or `clang`. Currently tested only under Linux, but porting to other systems shouldn't be difficult.

For sysadmins, to install in `/usr/local/{include,lib,bin}`:

        ./configure && make -j8 install

For developers with an unprivileged account (typically with

        export LD_LIBRARY_PATH="$HOME/lib"
        export LIBRARY_PATH="$HOME/lib"
        export CPATH="$HOME/include"
        export PATH="$HOME/bin:$PATH"

in `$HOME/.profile`), to install in `$HOME/{include,lib,bin}`:

        ./configure --prefix=$HOME && make -j8 install

For distributors creating a package: Run

        ./configure --prefix=/usr && make -j8

and then follow your usual packaging procedures for the `build/0/package` files:

        build/0/package/man/man3/cpucycles.3
        build/0/package/include/cpucycles.h
        build/0/package/lib/libcpucycles*
        build/0/package/bin/cpucycles-info

There are some old systems where libcpucycles requires `-lrt` for `clock_gettime`; currently `libcpucycles.so` doesn't link to `-lrt`, so it's up to the caller to link to `-lrt`.

More options: You can run

        ./configure --host=amd64

to override `./configure`'s guess of the architecture that it should compile for. The architecture controls which cycle counters to try compiling: e.g., `amd64` tries compiling `cpucycles/amd64*` and `cpucycles/default*`.

Inside the `build` directory, `0` is symlinked to `amd64` for `--host=amd64`. Running `make clean` removes `build/amd64`. Re-running `./configure` automatically starts with `make clean`.

A subsequent `./configure --host=arm64` will create `build/arm64` and symlink `0 -> arm64`, without touching an existing `build/amd64`. However, cross-compilers aren't yet selected automatically.

Compilers tried are listed in `compilers/default`. Each compiler includes `-fPIC` to create a shared library, `-fvisibility=hidden` to hide non-public symbols in the library, and `-fwrapv` to switch to a slightly less dangerous version of C. The first compiler that seems to work is used to compile everything.

Version: This is version 2023.01.05 of the "Install" web page.