INTDOS(DOS) XENIX System V INTDOS(DOS)
Name
intdos - Invokes a DOS system call.
Syntax
#include <dos.h>
int intdos (inregs, outregs);
union REGS *inregs;
union REGS *outregs;
Description
The intdos function invokes the DOS system call specified by
register values defined in inregs and returns the effect of
the system call in outregs. The inregs and outregs
arguments are unions of type REGS. The union type is
defined in the include file dos.h.
To invoke a system call, intdos executes an INT 21H
instruction. Before executing the instruction, the function
copies the contents of inregs to the corresponding
registers. After the INT instruction returns, intdos copies
the current register values to outregs. It also copies the
status of the system carry flag to the cflag field in
outregs. If this field is nonzero, the flag was set by the
system call and indicates an error condition.
intdos is intended to be used to invoke DOS system calls
that take arguments in registers other than DX (DH/DL) and
AL, or to invoke system calls that indicate errors by
setting the carry flag.
Return Value
intdos returns the value of the AX register after the system
call has completed. If the flag field in outregs is
nonzero, an error has occurred and doserrno is also set to
the corresponding error code.
See Also
bdos(DOS), int86(DOS), int86x(DOS), intdosx(DOS)
Page 1 (printed 8/7/87)
INTDOS(DOS) XENIX System V INTDOS(DOS)
Example
#include <dos.h> #include <stdio.h>
union REGS inregs, outregs; . . .
/* The following statements get the current date using **
dos function call 2a hex. */
inregs.h.ah = 0x2a; intdos (&inregs,&outregs); printf ("date
is %d/%d/%d\n",outregs.h.dh,outregs.h.dl,
outregs.x.cx);
Notes
This call must be compiled with the -dos flag.
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