/***
*_strerr.c - routine for indexing into system error list
*
*   Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
*   Returns system error message index by errno; conforms to the
*   XENIX standard, much compatibility with 1983 uniforum draft standard.
*
*Revision History:
*   02-24-87  JCR   Renamed this routine from "strerror" to "_strerror"
*                   for MS. The new "strerror" routine conforms to the
*                   ANSI interface.
*   11-10-87  SKS   Remove IBMC20 switch
*   12-11-87  JCR   Added "_LOAD_DS" to declaration
*   01-05-87  JCR   Mthread support
*   05-31-88  PHG   Merged DLL and normal versions
*   06-06-89  JCR   386 mthread support
*   11-20-89  GJF   Fixed copyright, indents. Removed unreferenced local.
*                   Added const attribute to type of message
*   03-13-90  GJF   Replaced _LOAD_DS with _CALLTYPE1, added #include
*                   <cruntime.h> and removed #include <register.h>
*   07-25-90  SBM   Removed redundant include (stdio.h)
*   10-04-90  GJF   New-style function declarator.
*   07-18-91  GJF   Multi-thread support for Win32 [_WIN32_].
*   02-17-93  GJF   Changed for new _getptd().
*   04-06-93  SKS   Replace _CRTAPI* with __cdecl
*   09-06-94  CFW   Remove Cruiser support.
*   09-06-94  CFW   Replace MTHREAD with _MT.
*   01-10-95  CFW   Debug CRT allocs.
*   29-11-99  GB    Added support for wide char by adding _wcserror() 
*
*******************************************************************************/

#include <cruntime.h>
#include <stdlib.h>
#include <errmsg.h>
#include <syserr.h>
#include <string.h>
#include <tchar.h>
#include <malloc.h>
#include <mtdll.h>
#include <dbgint.h>

/* Max length of message = user_string(94)+system_string+2 */
/* [NOTE: The mthread error message buffer is shared by both strerror
   and _strerror so must be the max length of both. */
#define _ERRMSGLEN_ 94+_SYS_MSGMAX+2

#ifdef _UNICODE
#define _terrmsg    _werrmsg
#else
#define _terrmsg    _errmsg
#endif


/***
*char *_strerror(message) - get system error message
*
*Purpose:
*   builds an error message consisting of the users error message
*   (the message parameter), followed by ": ", followed by the system
*   error message (index through errno), followed by a newline.  If
*   message is NULL or a null string, returns a pointer to just
*   the system error message.
*
*Entry:
*   char *message - user's message to prefix system error message
*
*Exit:
*   returns pointer to static memory containing error message.
*   returns NULL if malloc() fails in multi-thread versions.
*
*Exceptions:
*
*******************************************************************************/

#ifdef _UNICODE
wchar_t * __cdecl __wcserror(
#else
char * __cdecl _strerror (
#endif
    REG1 const _TCHAR *message
    )
{
#ifdef  _MT

    _ptiddata ptd = _getptd();
    _TCHAR *bldmsg;

#else

    static _TCHAR bldmsg[_ERRMSGLEN_];

#endif


#ifdef  _MT

    /* Use per thread buffer area (malloc space, if necessary) */
    /* [NOTE: This buffer is shared between _strerror and streror.] */

    if ( (ptd->_terrmsg == NULL) && ((ptd->_terrmsg =
            _malloc_crt(_ERRMSGLEN_ * sizeof(_TCHAR))) == NULL) )
            return(NULL);
    bldmsg = ptd->_terrmsg;

#endif

    /* Build the error message */

    bldmsg[0] = '\0';

    if (message && *message) {
        _tcscat( bldmsg, message );
        _tcscat( bldmsg, _T(": "));
    }

#ifdef _UNICODE
    mbstowcs(bldmsg + wcslen(bldmsg), _sys_err_msg( errno ), _ERRMSGLEN_ - wcslen(bldmsg));
#else
    strcat( bldmsg, _sys_err_msg( errno ) );
#endif
    return( _tcscat( bldmsg, _T("\n")) );
}