C++ variant of threads-intro/t1.c (Figure 26.6)

Makefile

CXXFLAGS = -g -std=c++17 -Wall -Wextra -Wpedantic -Werror -pthread

all: t1 t1-sanitized

# Note: using implicit rule for .cpp files to create t1

t1-sanitized: t1.cpp
	$(CXX) $(CXXFLAGS) -o $@ $^ -fsanitize=thread

.PHONY: clean

clean:
	rm -f t1 t1-sanitized

t1.cpp

#include <cstdlib>
#include <cassert>

#include <iostream>

#include <pthread.h>

using std::cout;
using std::cerr;
using std::endl;

inline int Pthread_create(pthread_t *thread, const pthread_attr_t *attr,
        void *(*start_routine) (void *), void *arg) {
    int rc = pthread_create(thread, attr, start_routine, arg);
    assert(rc == 0);
    return rc;
}

inline int Pthread_join(pthread_t thread, void **value_ptr) {
    int rc = pthread_join(thread, value_ptr);
    assert(rc == 0);
    return rc;
}

int max;
volatile int counter = 0;

void *mythread(void *arg) {
    char *letter = reinterpret_cast<char *>(arg);
    int i;
    cout << letter << ": begin [addr of i: " << &i << "]" << endl;
    for (i = 0; i < max; i++) {
        counter = counter + 1;
    }
    cout << letter << ": done" << endl;
    return NULL;
}

int main(int argc, char *argv[]) {
    if (argc != 2) {
        cerr << "usage: main-first <loopcount>" << endl;
        exit(EXIT_FAILURE);
    }
    max = atoi(argv[1]);

    pthread_t p1, p2;
    cout << "main: begin [counter = " << counter << "] ["
        << reinterpret_cast<unsigned long int>(&counter) << "]" << endl;
    Pthread_create(&p1, NULL, mythread, const_cast<char *>("A"));
    Pthread_create(&p2, NULL, mythread, const_cast<char *>("B"));
    Pthread_join(p1, NULL);
    Pthread_join(p2, NULL);
    cout << "main: done\n [counter: " << counter << "]\n [should: "
        << max*2 << "]" << endl;

    return EXIT_SUCCESS;
}