BDOS(DOS) XENIX System V BDOS(DOS)
Name
bdos - Invokes a DOS system call.
Syntax
#include <dos.h>
int bdos (dosfn, dosdx, dosal);
int dosfn;
unsigned int dosdx;
unsigned int dosal;
Description
The bdos function invokes the MS-DOS system call specified
by dosfn after placing the values specified by dosdx and
dosal in the DX and AL registers, respectively. bdos
executes an INT 21H instruction to invoke the system call.
When the system call returns, bdos returns the content of
the AX register.
bdos is intended to be used to invoke DOS system calls that
either take no arguments or only take arguments in the DX
(DH,DL) and/or AL registers.
Return Value
bdos returns the value of the AX register after the system
call has completed.
See Also
intdos(DOS), intdosx(DOS)
Example
#include <bdos.h>
char *buffer = "Enter file name:$";
/* AL is not needed, so 0 is used */ bdos (9,
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BDOS(DOS) XENIX System V BDOS(DOS)
(unsigned) buffer, 0);
Notes
This call should not be used to invoke system calls that
indicate errors by setting the carry flag. Since C programs
do not have access to this flag, the status of the return
value cannot be determined. The intdos function should be
used in these cases.
This call must be compiled with the -dos flag.
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