View source for VIO Tutorial (Hello, World)

''By [[User:Myrkraverk|Johann Oskarsson]]''

This is a short tutorial on writing text to the console, the basics, and then with some color and cursor positioning.
* All examples have been compiled with [[OpenWatcom]].
VIO is short for Video Input/Output, and is the console interface to eCS.

The following is a hello, world application for the eCS VIO API.
<code>
 #define INCL_VIO
 #include <os2.h>
 
 int main( int argc, char *argv[] )
 {
 	APIRET rc = VioWrtTTY( "Hello, VIO\n", // string to write
 	                       11,             // lenght of string to write
 	                       0 );            // VIO handle, must be 0
 	return rc;
 }
</code>    
This can be compiled with OpenWatcom 1.3, as such: <tt>WCL386 vio.cpp</tt>, assuming the file name of vio.cpp.

Because of the non-standard style comments (double slash format) the option for the IBM C compiler should be: <tt>icc /Ss+ vio.c</tt>

==Character Attributes==
;Lower Nibble (Character)
* Bit 0: Blue (0x01)
* Bit 1: Green (0x02)
* Bit 2: Red (0x04)
* Bit 3: Intensity (0x08)
;Higher Nibble (Background)
* Bit 4: Blue (0x10)
* Bit 5: Green (0x20)
* Bit 6: Red (0x40)
* Bit 7: Blink/Intensity (0x80) (VioSetState)

==Color Example==
<code>
 #define INCL_VIO
 #include <os2.h>
 
 int main( int argc, char *argv[] )
 {
    char buffer[32] = {
        'H', 12,       // intense red
        'e', 9,        // intense blue
        'l', 10,       // intense green
        'l', 12,
        'o', 9,
        ',', 10,
        ' ', 0,
        'i', 12,
        'n', 9,
        ' ', 0,
        'c', 10,
        'o', 12,
        'l', 9,
        'o', 10,
        'r', 12,
        '!', 9 };
 
     APIRET rc = VioWrtCellStr( buffer,
         32,         // Buffer length
         3,          // Row, 3 to allow some scrolling
         0,          // Column
         0 );        // VioHandle, must be 0
 
     return rc;
 }
</code>

[[Category:C Articles]]