OpenMP installation test file with generic Makefile

main.cpp

#include <iostream>

#include <omp.h>

int main() {

#pragma omp parallel
  {
    const auto ncpu = omp_get_num_procs();
    const auto tid = omp_get_thread_num();
    const auto npr = omp_get_num_threads();
    const auto nthr = omp_get_max_threads();

#pragma omp single
    {
      std::cout << tid << ": NCPU\t= " << ncpu << std::endl;
      std::cout << tid << ": NTHR\t= " << nthr << std::endl;
      std::cout << tid << ": NPR\t= " << npr << std::endl;
    }

#pragma omp critical
    std::cout << tid << ": Thread n°" << tid << "/" << npr << " in OpenMP stage 1" << std::endl;
  }
  return 0;
}

Makefile

BIN?=main
CXX?=clang++
EXT?=cpp
LINKS?=

SRCS=$(shell find . -name "*."$(EXT))
DIRS=$(shell find ./* -type d)
OBJS=$(patsubst %.$(EXT),%.o,$(SRCS))
INCS=$(addprefix -I, $(DIRS))

CPPFLAGS+=-std=c++17 -Wall -fopenmp $(INCS)
LDFLAGS+=$(addprefix -l, $(LINKS))

.PHONY: all run clean

all: $(BIN)

$(EXT).o: $(SRCS)
	$(CXX) $(CPPFLAGS) -c $<

$(BIN): $(OBJS)
	$(CXX) $(CPPFLAGS) -o $(BIN) $(notdir $(OBJS)) $(LDFLAGS)

run: all
	-./$(BIN)

clean:
	-rm -f $(notdir $(OBJS)) $(BIN)