WCSFTIME_WCHAR_T_FMAT.cpp

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// checking for wcsftime() in <wchar.h>
 
 
#include "config.h"
 
#if    defined (__EDG__)                \
    && !defined (__DECCXX)              \
    && !defined (__HP_aCC)              \
    && !defined (__INTEL_COMPILER)      \
    && !defined (_SGI_COMPILER_VERSION)
   // disable error #450-D: the type "long long" is nonstandard
   // when using the vanilla EDG eccp in strict mode (i.e., w/o
   // long long support)
#  pragma diag_suppress 450
#endif   // EDG eccp on Linux
 
#include <stddef.h>   // for size_t
#include <stdio.h>    // for printf()
#include <time.h>     // for struct tm
 
#ifndef _RWSTD_NO_WCSFTIME
#  ifndef _RWSTD_NO_WCHAR_H
#    include <wchar.h>    // for wcsftime()
#  else   // if defined (_RWSTD_NO_WCHAR_H)
#    include <stdlib.h>   // for wcsftime()
#  endif   // _RWSTD_NO_WCHAR_H
 
 
#ifndef _RWSTD_NO_NAMESPACE
 
namespace std { }
using namespace std;
 
#endif   // _RWSTD_NO_NAMESPACE
 
 
extern "C" {
 
typedef size_t (f_w)(wchar_t*, size_t, const wchar_t*, const struct tm*);
typedef size_t (f_c)(wchar_t*, size_t, const char*, const struct tm*);
 
}
 
 
const char* foo (f_w*) { return "const wchar_t*"; }
 
const char* foo (f_c*) { return "const char*"; }
 
 
const char* bar ()
{
    // 7.16.6 of C95
    // 7.24.5.1 of C99
    return foo (&wcsftime);
}
 
 
int main ()
{
    const char *argtype = bar ();
    if (*(argtype+6) == 'c') {
       printf ("#define _RWSTD_NO_WCSFTIME_WCHAR_T_FMAT\n");
    }
 
    printf ("#define _RWSTD_WCSFTIME_ARG3_T %s\n", argtype);
 
    return 0;
}
 
#else   // if defined (_RWSTD_NO_WCSFTIME)
 
extern "C" size_t wcsftime (wchar_t*, size_t, const wchar_t*, const struct tm*);
 
struct tm t;
 
int main ()
{
    wchar_t buf [40] = { 0 };
 
    // format using a wchar_t format string; if the function takes
    // a whar_t* argument, it will format as expected, otherwise
    // it will format at most one character (unless sizeof (char)
    // == sizeof (wchar_t))
    size_t n = wcsftime (buf, sizeof buf, L"abc", &t);
 
    const char *argtype;
 
    if (   3    == n
        && wchar_t ('a')  == buf [0]
        && wchar_t ('b')  == buf [1]
        && wchar_t ('c')  == buf [2]
        && wchar_t ('\0') == buf [3])
        argtype = "const wchar_t*";
    else {
        argtype = "const char*";
 
        printf ("#define _RWSTD_NO_WCSFTIME_WCHAR_T_FMAT\n");
 
    }
 
    printf ("#define _RWSTD_WCSFTIME_ARG3_T %s\n", argtype);
 
    return 0;
}
 
#endif   // _RWSTD_NO_WCSFTIME