Compile and run

users guide

To compile and run a program using OpenCilk, follow these two
steps:

  1. Compile the Cilk program using the
    OpenCilk compiler by passing the additional -fopencilk compiler
    flag, then
  2. Run the resulting executable.

This page provides details on how to compile and run a Cilk program
using OpenCilk.

Compiling a Cilk program

You can compile a Cilk program similarly to a C or C++ program by
passing the additional -fopencilk flag to clang or clang++,
respectively:

$ clang -o fib fib.c -fopencilk -O3

"Note"

Pass the -fopencilk flag
to the compiler both when compiling and linking the Cilk program.
During compilation, the flag ensures that the Cilk keywords are
recognized and compiled. During linking, the flag links ensures the
program is properly linked with the OpenCilk runtime library.

The OpenCilk compiler is based on a recent stable version of the clang
compiler. It supports all compiler flags and features that the
ordinary clang compiler supports, including optimization-level flags,
debug-information flags, and target-dependent compilation options.
See the Clang
documentation
for more information on the command-line arguments.

Running a Cilk program

To run the Cilk program, simply invoke the compiled executable binary:

$ ./fib 42

You can use the CILK_NWORKERS environment variable to run the Cilk
program with a specific number of workers. The following example runs
the fib executable using 8 Cilk workers:

$ CILK_NWORKERS=8 ./fib 42