What is REGS

[caroundw5h]

coding an example from a book and i get the message

storage size of 'regs' not known

wondering why i get this if it supposed to return the dos version i am on.

/* gets DOS version and number */


#include <stdio.h>
#include <dos.h>


int main()

{

int major, minor;
union REGS regs;      // required for making DOS calls


regs.h.a=1;            // GET VERSION NUMBER
regs.h.ah=0x30;       //get version function 30h
int86(0x21,&regs,&regs);   // call DOS


major=regs.h.al;           // major version number
minor=regs.h.ah;           // minor version number

printf("This is DOS version %i, release %i\n", major, minor);


return 0;

}

[orbitz]

What book is this? dos.h is not a standard header, is it defined in your book? Are there any other headers included that you left out? Is this the exact copy from your book? Does the index say anything abotu REGS? Can you provide any more information at all?

[caroundw5h]

The dos.h is a standard header on my compiler Devc++, don't know if its compiler specific though. Probably is. anyway WYSIWYG in terms of the code i posted. That is exactly how it was done. What other info do you need?

[Shadow]

Originally posted by caroundw5h
The dos.h is a standard header on my compiler Devc++, don't know if its compiler specific though.

Isn't this an oxymoron?

[Prelude]

>Isn't this an oxymoron?
It depends on your definition of standard.

[Shadow]

Well, he said that dos.h is standard on his compiler. So, isn't this an oxymoron? I always thought stdio.h, for example, was standard, because it's just standard. Every darn compiler "has it." For example, even though quite a few compilers have conio.h, conio.h is not standard.

[WaltP]

No, dos.h is NOT a standard header. It was added to various compilers to enhance the C language. I'll bet the book was written for Borland or Turbo C and you are not using these compilers. The implementation of dos.h is completely up to the compiler designers so your implementation is not the same as the compiler the book used.

Read the requirements of the book to find out which compiler you should be using.

[VirtualAce]

Go into your dos.h and view it in your IDE or a text editor. You should find the structure for REGS there.

[jim mcnamara]

What you're writing is straight Turbo C code for DOS.

REGS is a union of two structs - WORDREGS which is 7 unsigned 16 byte ints, and BYTEREGS which is a struct of 8 unsigned chars.

int86 will not work under Win2K and XP. Some interrupts may work, but not all.

Your problem is that you declare major & minor as signed int.
reg.h.al is an unsigned char.