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─────Run-Time Library───────────────────────────────────────────────────────
 
/* WPRINTF.C shows how to use vprintf functions to write new versions
 * of printf. Functions illustrated include:
 *      vsprintf        vprintf         vfprintf
 *
 * The vsprintf function is used in the example. The other variations
 * can be used similarly. For other examples of formatted output,
 * see EXTDIR.C (sprintf), TABLE.C (fprintf), and PRINTF.C.
 */
 
#include <stdio.h>
#include <graph.h>
#include <string.h>
#include <stdarg.h>
#include <malloc.h>
 
int wprintf( short row, short col, short clr, long bclr, char *fmt, ... );
 
void main()
{
    short fgd = 0;
    long  bgd = 0L;
 
    _clearscreen( _GCLEARSCREEN );
    _outtext( "Color text example:\n\n" );
 
    /* Loop through 8 background colors. */
    for( bgd = 0L; bgd < 8; bgd++ )
    {
        wprintf( (int)bgd + 3, 1, 15, bgd, "Back: %d Fore:", bgd );
 
        /* Loop through 16 foreground colors. */
        for( fgd = 0; fgd < 16; fgd++ )
            wprintf( -1, -1, fgd, -1L, " %2d ", fgd );
    }
}
 
/* Full-screen window version of printf that takes row, column, textcolor,
 * and background color as its first arguments, followed by normal printf
 * format strings (except that \t is not handled). You can specify -1 for
 * any of the first arguments to use the current value. The function returns
 * the number of characters printed, or a negative number for errors.
 */
int wprintf( short row, short col, short clr, long bclr, char *fmt, ... )
{
    struct  _rccoord tmppos;
    short   ret, size;
    va_list marker;
    char    *buffer;
 
    /* It's probably safe to use a buffer length of 512 bytes or five times
     * the length of the format string.
     */
    size = strlen( fmt );
    size = (size > 512) ? 512 : size * 5;
    if( (buffer = (char *)malloc( size )) == NULL )
        return -1;
 
    /* Set text position. */
    tmppos = _gettextposition();
    if( row < 1 )
        row = tmppos.row;
    if( col < 1 )
        col = tmppos.col;
    _settextposition( row, col );
 
    /* Set foreground and background colors. */
    if( clr >= 0 )
        _settextcolor( clr );
    if( bclr >= 0 )
        _setbkcolor( bclr );
 
    /* Write text to a string and output the string. */
    va_start( marker, fmt );
    ret = vsprintf( buffer, fmt, marker );
    va_end( marker );
    _outtext( buffer );
    free( buffer );
    return ret;
}
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