reference, declaration → definition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced

    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42

#include <cstdio>
#include <string>
#include <vector>

// If we have libc++ 4.0 or greater we should have <optional>
// According to libc++ C++1z status page https://libcxx.llvm.org/cxx1z_status.html
#if _LIBCPP_VERSION >= 4000
#include <optional>
#define HAVE_OPTIONAL 1
#else
#define HAVE_OPTIONAL 0
#endif


int main()
{
    bool has_optional = HAVE_OPTIONAL ;

    printf( "%d\n", has_optional ) ; // break here

#if HAVE_OPTIONAL == 1
    using int_vect = std::vector<int> ;
    using optional_int = std::optional<int> ;
    using optional_int_vect = std::optional<int_vect> ;
    using optional_string = std::optional<std::string> ;

    optional_int number_not_engaged ;
    optional_int number_engaged = 42 ;

    printf( "%d\n", *number_engaged) ;

    optional_int_vect numbers{{1,2,3,4}} ;

    printf( "%d %d\n", numbers.value()[0], numbers.value()[1] ) ;

    optional_string ostring = "hello" ;

    printf( "%s\n", ostring->c_str() ) ;
#endif

    return 0; // break here
}