Programming Forums > Application Development > C

matko · Jan 21st, 2006, 4:00 PM

Can anyone tell me wha next code doesn't compile:

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

union REGS regs;

main(argc, argv)
int argc;
char *argv[];
{
	if (argc == 2)
		modeset(atoi(argv[1]));

	if (argc != 2)
		printf("EGA Mode is %d", modeget());
}

modeset(mode)
int mode;
{
	regs.h.a1 = mode;
	regs.h.ah = 0;
	int86(0x10, &regs, &regs);
}

modeget(){
regs.h.a1 = 0;
regs.h.ah = 0x0f;
int86(0x10, &regs, &regs);
return(regs.h.a1);
}

Kaja Fumei · Jan 21st, 2006, 4:15 PM

The list of compiler errors would help so I don't have to go looking through dos.h

matko · Jan 21st, 2006, 4:29 PM

--------------------Configuration: MODEGA - Win32 Debug--------------------
Compiling...
MODEGA.C
D:\zabavni_projekti\MODEGA.C(4) : error C2079: 'regs' uses undefined union 'REGS'
D:\zabavni_projekti\MODEGA.C(11) : warning C4013: 'modeset' undefined; assuming extern returning int
D:\zabavni_projekti\MODEGA.C(11) : warning C4013: 'atoi' undefined; assuming extern returning int
D:\zabavni_projekti\MODEGA.C(14) : warning C4013: 'modeget' undefined; assuming extern returning int
D:\zabavni_projekti\MODEGA.C(20) : error C2224: left of '.h' must have struct/union type
D:\zabavni_projekti\MODEGA.C(21) : error C2224: left of '.h' must have struct/union type
D:\zabavni_projekti\MODEGA.C(22) : warning C4013: 'int86' undefined; assuming extern returning int
D:\zabavni_projekti\MODEGA.C(26) : error C2224: left of '.h' must have struct/union type
D:\zabavni_projekti\MODEGA.C(27) : error C2224: left of '.h' must have struct/union type
D:\zabavni_projekti\MODEGA.C(29) : error C2224: left of '.h' must have struct/union type
D:\zabavni_projekti\MODEGA.C(29) : warning C4033: 'modeget' must return a value
Error executing cl.exe.

MODEGA.OBJ - 6 error(s), 5 warning(s)

Ooble · Jan 21st, 2006, 7:22 PM

Looks like Visual C++ to me. No one's supported DOS.H for absolutely ages - it's ancient. Now, why would you want to check for EGA mode when you're running Windows?

Kaja Fumei · Jan 21st, 2006, 10:40 PM

1. Try "union _REGS" instead of "union REGS"
2. Try "_int86" instead of "int86".
3. You need to include stdlib.h to use atoi()
4. You either need to declare prototypes for modeget and modeset before they are used (or you could just move main to the bottom of the file).
5. modeget is declared to return a int. If you forgot to return the value, put it in. If there is nothing to return, the return type should be "void".

grumpy · Jan 22nd, 2006, 1:04 AM

Close Kaja. modeset() can be declared void with modern compilers. modeget() is returning a value.

The basic problem, as Ooble has said, is that this is code that worked with an ancient compiler not working with a modern compiler. The form of function definitions;

(Toggle Plain Text)

main(argc, argv)
int argc;
char *argv[];

were deprecated (a formal way of declaring them obsolete to discourage their use) in the 1989 C standard, in favour of;

(Toggle Plain Text)

int main(int argc, char *argv[])

style. This suggests the original code is at least 15 years old. One reason that the functions haven't been declared void is that compilers of that vintage did not support the void keyword.

ivan · Jan 22nd, 2006, 5:51 AM

Quote:

Originally Posted by matko

--------------------Configuration: MODEGA - Win32 Debug--------------------
Compiling...
MODEGA.C
D:\zabavni_projekti\MODEGA.C(4) : error C2079: 'regs' uses undefined union 'REGS'
D:\zabavni_projekti\MODEGA.C(11) : warning C4013: 'modeset' undefined; assuming extern returning int
D:\zabavni_projekti\MODEGA.C(11) : warning C4013: 'atoi' undefined; assuming extern returning int
D:\zabavni_projekti\MODEGA.C(14) : warning C4013: 'modeget' undefined; assuming extern returning int
D:\zabavni_projekti\MODEGA.C(20) : error C2224: left of '.h' must have struct/union type
D:\zabavni_projekti\MODEGA.C(21) : error C2224: left of '.h' must have struct/union type
D:\zabavni_projekti\MODEGA.C(22) : warning C4013: 'int86' undefined; assuming extern returning int
D:\zabavni_projekti\MODEGA.C(26) : error C2224: left of '.h' must have struct/union type
D:\zabavni_projekti\MODEGA.C(27) : error C2224: left of '.h' must have struct/union type
D:\zabavni_projekti\MODEGA.C(29) : error C2224: left of '.h' must have struct/union type
D:\zabavni_projekti\MODEGA.C(29) : warning C4033: 'modeget' must return a value
Error executing cl.exe.

MODEGA.OBJ - 6 error(s), 5 warning(s)

We speak the same language

matko · Jan 22nd, 2006, 8:58 AM

Which is that ancient compiler? Where can I get(download) it?
Is Turbo C sufficient?

Ooble · Jan 22nd, 2006, 2:07 PM

Why would you want to run this program within Windows anyway? EGA is a buzzword for a 640x350 resolution with 4-bit colour. It's been obsolete since 1990 at the very latest.

DaWei · Jan 24th, 2006, 8:05 AM

An ancient compiler isn't necessarily good enough. The code emitted would in many cases be regurgitated at runtime by today's more protective OSes.

Jan 21st, 2006, 4:00 PM	#1
matko Newbie Join Date: Sep 2005 Posts: 28 Rep Power: 0	EGA mode Can anyone tell me wha next code doesn't compile: (Toggle Plain Text) #include <stdio.h> #include <dos.h> union REGS regs; main(argc, argv) int argc; char argv[]; { if (argc == 2) modeset(atoi(argv[1])); if (argc != 2) printf("EGA Mode is %d", modeget()); } modeset(mode) int mode; { regs.h.a1 = mode; regs.h.ah = 0; int86(0x10, &regs, &regs); } modeget(){ regs.h.a1 = 0; regs.h.ah = 0x0f; int86(0x10, &regs, &regs); return(regs.h.a1); } #include <stdio.h> #include <dos.h> union REGS regs; main(argc, argv) int argc; char argv[]; { if (argc == 2) modeset(atoi(argv[1])); if (argc != 2) printf("EGA Mode is %d", modeget()); } modeset(mode) int mode; { regs.h.a1 = mode; regs.h.ah = 0; int86(0x10, &regs, &regs); } modeget(){ regs.h.a1 = 0; regs.h.ah = 0x0f; int86(0x10, &regs, &regs); return(regs.h.a1); }

Jan 21st, 2006, 7:22 PM	#4
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	Looks like Visual C++ to me. No one's supported DOS.H for absolutely ages - it's ancient. Now, why would you want to check for EGA mode when you're running Windows? __________________ Me :: You :: Them

Jan 22nd, 2006, 1:04 AM	#6
grumpy Programming Guru Join Date: Jun 2005 Location: Adelaide, South Australia Posts: 1,198 Rep Power: 5	Close Kaja. modeset() can be declared void with modern compilers. modeget() is returning a value. The basic problem, as Ooble has said, is that this is code that worked with an ancient compiler not working with a modern compiler. The form of function definitions; (Toggle Plain Text) main(argc, argv) int argc; char argv[]; main(argc, argv) int argc; char argv[]; were deprecated (a formal way of declaring them obsolete to discourage their use) in the 1989 C standard, in favour of; (Toggle Plain Text) int main(int argc, char argv[]) int main(int argc, char argv[]) style. This suggests the original code is at least 15 years old. One reason that the functions haven't been declared void is that compilers of that vintage did not support the void keyword.

Jan 22nd, 2006, 2:07 PM	#9
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	Why would you want to run this program within Windows anyway? EGA is a buzzword for a 640x350 resolution with 4-bit colour. It's been obsolete since 1990 at the very latest. __________________ Me :: You :: Them

Jan 24th, 2006, 8:05 AM	#10
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	An ancient compiler isn't necessarily good enough. The code emitted would in many cases be regurgitated at runtime by today's more protective OSes. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Jan 21st, 2006, 4:15 PM	#2
Kaja Fumei Hobbyist Programmer Join Date: Oct 2005 Posts: 134 Rep Power: 3	The list of compiler errors would help so I don't have to go looking through dos.h

Jan 21st, 2006, 4:29 PM	#3
matko Newbie Join Date: Sep 2005 Posts: 28 Rep Power: 0	--------------------Configuration: MODEGA - Win32 Debug-------------------- Compiling... MODEGA.C D:\zabavni_projekti\MODEGA.C(4) : error C2079: 'regs' uses undefined union 'REGS' D:\zabavni_projekti\MODEGA.C(11) : warning C4013: 'modeset' undefined; assuming extern returning int D:\zabavni_projekti\MODEGA.C(11) : warning C4013: 'atoi' undefined; assuming extern returning int D:\zabavni_projekti\MODEGA.C(14) : warning C4013: 'modeget' undefined; assuming extern returning int D:\zabavni_projekti\MODEGA.C(20) : error C2224: left of '.h' must have struct/union type D:\zabavni_projekti\MODEGA.C(21) : error C2224: left of '.h' must have struct/union type D:\zabavni_projekti\MODEGA.C(22) : warning C4013: 'int86' undefined; assuming extern returning int D:\zabavni_projekti\MODEGA.C(26) : error C2224: left of '.h' must have struct/union type D:\zabavni_projekti\MODEGA.C(27) : error C2224: left of '.h' must have struct/union type D:\zabavni_projekti\MODEGA.C(29) : error C2224: left of '.h' must have struct/union type D:\zabavni_projekti\MODEGA.C(29) : warning C4033: 'modeget' must return a value Error executing cl.exe. MODEGA.OBJ - 6 error(s), 5 warning(s)

Jan 21st, 2006, 10:40 PM	#5
Kaja Fumei Hobbyist Programmer Join Date: Oct 2005 Posts: 134 Rep Power: 3	1. Try "union _REGS" instead of "union REGS" 2. Try "_int86" instead of "int86". 3. You need to include stdlib.h to use atoi() 4. You either need to declare prototypes for modeget and modeset before they are used (or you could just move main to the bottom of the file). 5. modeget is declared to return a int. If you forgot to return the value, put it in. If there is nothing to return, the return type should be "void".

Jan 22nd, 2006, 8:58 AM	#8
matko Newbie Join Date: Sep 2005 Posts: 28 Rep Power: 0	Which is that ancient compiler? Where can I get(download) it? Is Turbo C sufficient?

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