/*

$ g++ errno_exception.cc; ./a.out
Tentando alocar memoria ...
error code(12): Cannot allocate memory
Tentando abrir um arquivo ...
error code(2): No such file or directory

*/

#include <iostream>
#include <cstring>

#include <errno.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include <stdlib.h>

class sys_err {
	public:
		inline int code(void){ return errno; };
		inline char * description(){ return strerror(errno); }
};

std::ostream& operator << (std::ostream& o , class sys_err z){
	o << "error code(" << z.code() << "): " << z.description() << "\n";
	return o;
}

int main(void){

	try {
		std::cout << "Tentando alocar memoria ...\n";

		char *z = (char *)malloc((size_t)-1);
		if(z == NULL){
			throw sys_err();
		}

        free(z);

	}

	catch(sys_err& e){
		std::cerr << e;
	}

	try {
		std::cout << "Tentando abrir um arquivo ...\n";

		int fd = open("/a/b/c/d", O_RDONLY);
        if(fd == -1){
            throw sys_err();
        }

	}

	catch(sys_err& e){
		std::cerr << e;
	}

}