Watcom C Library Reference : _bgetcmd, _bheapseg, _bios_disk, _bios_equiplist
Watcom C Reference/A - B - C 2021. 6. 15. 18:56
WATCOM C Library Reference : _bgetcmd, _bheapseg, _bios_disk, _bios_equiplist
_bgetcmd
Synopsis : #include <process.h>
int _bget cmd( char *cmd_line, int len );
Description : The _bgetcmd function causes the command line information, with the program name removed, to be copied to cmd_line. The argument len specifies the size of cmd_line.
The information is terminated with a '\0' character. This provides a method of obtaining the original parameters to a program unchanged (with the white space intact).
This information can also be obtained by examining the vector of program parameters passed to the main function in the program.
Returns : If cmd line is NULL then the number of bytes required to store the command line, excluding the terminating NULL character, is returned; otherwise the number of bytes stored in cmd line, excluding the terminating NULL character, is returned.
See Also : abort, atexit, exec Functions, exit, _exit, get_cmd, getenv, main, onexit, putenv, spawn Functions, system
Example : Suppose a program were invoked with the command line
myprog arg-1 ( my stuff ) here
where that program contains
#include <stdio.h>
#include <stdlib.h>
#include <process.h>
void main( )
{
char *cmdline;
int cmdlen;
cmdlen = _bgetcmd( NULL, 0 ) + 1;
cmdline = malloc( cmdlen );
if( cmdline != NULL) {
cmdlen = _bgetcmd ( cmdline, cmdlen ) ;
printf( "%s\n", cmdline );
}
}
produces the following :
arg-1 ( my stuff ) here
Classification : WATCOM
Systems : All
_bheapseg
Synopsis : #include <malloc.h>
__segment bheapseg ( size_t size );
Description : The bheapseg function allocates a based-heap segment of at least size bytes.
The argument size indicates the initial size for the heap. The heap will automatically be enlarged as needed if there is not enough space available within the heap to satisfy an allocation request by _bcalloc, _bexpand, _bmalloc, or _brealloc.
The value returned by _bheapseg is the segment value or selector for the based heap. This Value must be saved and used as an argument to other based heap functions to indicate which based heap to operate upon.
Each call to _bheapseg allocates a new based heap.
Returns : The value returned by _bheapseg is the segment value or selector for the based heap. This value must be saved and used as an argument to other based heap functions to indicate which based heap to operate upon.
A special value of _NULLSEG is returned if the segmente could not be allocated.
See Also : _bfreeseg, _bcalloc, _bexpand, _bmalloc, _brealloc
Example :
#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
struct list {
struct list __based (__self) *next;
int value;
};
void main( )
{
int i;
__segment seg;
struct list __based (seg) *head;
struct list __based (seg) *p;
/* allocate based heap */
seg = _bheapseg ( 1024 );
if( seg == _NULLSEG ) {
printf( "Unable to allocate based heap\n" );
exit ( 1 );
}
/* create a linked list in the based heap */
head = 0;
for ( i = 1; i < 10; i++ ) {
P = _bralloc( seg, sizeof( struct list ) );
if( p == _NULLOFF ) {
printf( "_bmalloc failed\n" );
break;
}
p->next = head;
p->value = i;
head = p;
}
/* traverse1 the linked list, printing out values */
for( p = head; p != 0; p = p->next ) {
printf( "Value = %d\n", p->value );
}
/* free all the elements of the linked list */
for( ; p = head; ) {
head = p->next;
_bfree ( seg, p );
}
/* free the based heap */
_bfreeseg( seg );
}
Classification : WATCOM
Systems : DOS/16, Win/16, QNX/16, OS/2 1.x(all)
_bios_disk
Synopsis : #include <bios.h>
unsigned short _bios_disk( unsigned service, struct diskinfo_t *diskinfo );
struct diskinfo_t { /* disk parameters */
unsigned drive; /* drive number */
unsigned head; /* head number */
unsigned track; /* track number */
unsigned sector; /* sector number */
unsigned nsectors; /* number of sectors */
void __far *buffer; /* buffer address */
};
Description : The _bios_disk function uses INT 0x13 to provide access to the BIOS disk functions.
Information for the desired service is passed the diskinfo_t structure pointed to by diskinfo. The value for service can be one of the following values:
Value Meaning
_DISK_RESET Forces the disk controller to do a reset on the disk. This request does not use the diskinfo argument.
_DISK_STATUS Obtains the status of the last disk operation.
_DISK_READ Reads the specified number of sectors from the disk. This request users all of the information passed in the diskinfo structure.
_DISK_WRITE Writes the specified amount of data to the disk. This request uses allne the information passed in the diskinfo structure.
_DISK_VERIFY Checks the disk to be sure the specified sectors exist and can be read.
A CRC (cyclic redundancy check) test is performed. This request all of the information passed in the diskinfo structure except for the buffer field.
_DISK_FORMAT Formats the specified track on the disk. The head and track fields indicate the track to be formatted. Only one track can be formatted per call. The buffer field points to a set of sector markers, whose format depends on the type of disk drive. This service has no return value.
Returns : The _bios_disk function returns status information in the high-order byte when service is _DISK_STATUS, _DISK_READ, _DISK_WRITE, or _DISK_VERIFY. The possible values are:
Value Meaning
0x00 Operation successful
0x01 Bad command
0x02 Address mark not found
0x03 Attempt to write to write-protected disk
0x04 Sector not found
0x05 Reset failed
0x06 Disk changed since last operation
0x07 Drive parameter activity failed
0x08 DMA overrun
0x09 Attempt to DMA across 64K boundary
0x0A Bad sector detected
0x0B Bad track detected
0x0C Unsupported track
0x10 Data read (CRC/ECC) error
0x11 CRC/ECC corrected data error
0x20 Controller failure
0x40 Seek operation failed
0x80 Disk timed out or failed to respond
0xAA Drive not ready
0xBB Undefined error occurred
0xCC Write fault occurred
0xE0 Status error
0xFF Sense operation failed
Example :
#include <stdio.h>
#include <bios.h>
void main( )
{
struct diskinfo_t di;
unsigned short status;
di.drive = di.head = di.track = di.sector = 0;
di.nsectors = 1;
di.buffer = NULL;
status = _bios_disk ( _DISK_VERIFY, &di );
printf( "Status = 0x%4.4X\n", status );
}
Classification : BIOS
Systems : DOS, Win, NT, DOS/PM
_bios_equiplist
Synopsis : #include <bios.h>
unsigned short _bios_equiplist ( void );
Description : The _bios_equiplist function uses INT 0x11 to determine what hardware and peripherals are installed on the machine.
Returns : The _bios_equiplist function returns a set of bits indicating what is current installed on the machine. Those bits are defined as follows:
Bit Meaning
bit 0 Set to 1 if system boots from disk
bit 1 Set to 1 if a math coprocessor is installed
bits 2-3 Indicates motherboard RAM size
bits 4-5 Initial video mode
bits 6-7 Number of diskette drives
bit 8 Set to 1 if machine does not have DMA
bits 9-11 Number of serial ports
bit 12 Set to 1 if a game port is attached
bit 13 Set to 1 if a serial printer is attached
bits 14-15 Number of parallel printers installed
Example :
#include <stdio.h>
#include <bios.h>
void main( )
{
unsigned short equipment;
equipment = _bios_equiplist( );
printf( "Equipment flags = 0x%4.4X\n", equipment );
}
Classification : BIOS
Systems : DOS, Win, NT, DOS/PM
This manual describes the WATCOM C library for DOS, Windows, and OS/2, It includes the Standard C Library (as defined in the ANSI C Standard).
WATCOM C Language Reference manual describes the ANSI C Programming language and extensions to it which are supported by WATCOM C/C++ (32bit)
