DosQuerySysInfo

Returns values of static system variables.

Syntax

DosQuerySysInfo( ulStartIndex, ulLastIndex, pDataBuffer, ulDataBufferLength )

Parameters

ulStartIndex (ULONG) - input

Index of the first info to query.

ulLastIndex (ULONG) - input

Index of the last info to query. Equal to ulStartIndex if it is the only wanted info.

pDataBuffer (PVOID) - output

Address to a data buffer to put the information in.

ulDataBufferLengt (LONG) - input

Size of pDataBuffer. Valid values for ulStartIndex and ulLastIndex

No.	Name	Description	OS/2 Version
1	QSV_MAX_PATH_LENGTH	Maximum length of a path name (bytes). Use this when allocating filename buffers.	All
2	QSV_MAX_TEXT_SESSIONS	Maximum number of text sessions.	All
3	QSV_MAX_PM_SESSIONS	Maximum number of PM sessions.	All
4	QSV_MAX_VDM_SESSIONS	Maximum number of DOS sessions.	All
5	QSV_BOOT_DRIVE	Boot drive (1 = A:, 2 = B:, 3 = C, and so on).	All
6	QSV_DYN_PRI_VARIATION	Absolute(= 0)/Dynamic(= 1) priority.	All
7	QSV_MAX_WAIT	Maximum wait time (seconds).	All
8	QSV_MIN_SLICE	Minimum time slice allowed (milliseconds).	All
9	QSV_MAX_SLICE	Maximum time slice allowed (milliseconds).	All
10	QSV_PAGE_SIZE	Memory page size (bytes). Default 4096 bytes.	All
11	QSV_VERSION_MAJOR	Major version number.	All
12	QSV_VERSION_MINOR	Minor version number.	All
13	QSV_VERSION_REVISION	Revision letter.	All
14	QSV_MS_COUNT	Value of a 32-bit, free-running counter (milliseconds). Zero at boot time.	All
15	QSV_TIME_LOW	Low-order 32 bits of the time since January 1, 1980 (seconds).	All
16	QSV_TIME_HIGH	High-order 32 bits of the time since January 1, 1980 (seconds).	All
17	QSV_TOTPHYSMEM	Total number of bytes of physical memory.	All
18	QSV_TOTRESMEM	Total number of bytes of system-resident memory.	All
19	QSV_TOTAVAILMEM	Maximum number of bytes available for all processes in the system RIGHT NOW.	All
20	QSV_MAXPRMEM	Maximum number of bytes available for this process RIGHT NOW.	All
21	QSV_MAXSHMEM	Maximum number of shareable bytes available RIGHT NOW.	All
22	QSV_TIMER_INTERVAL	Timer interval (1/10 milliseconds).	All
23	QSV_MAX_COMP_LENGTH	Maximum length of one component in a path name (bytes).	All
24	QSV_FOREGROUND_FS_SESSION	Session ID of the current foreground full screen session. (any PM, VIO or Win-DOS session would be ID = 1).	Warp
25	QSV_FOREGROUND_PROCESS	Process ID of the current foreground process.	Warp
26	QSV_NUMPROCESSORS	Number of processors in the computer.	Warp
27	QSV_MAXHPRMEM	Maximum amount of free space in the high private arena for this process. This number does not indicate the largest single memory object that can be allocated, since the arena is probably fragmented.	Warp
28	QSV_MAXHSHMEM	Maximum amount of free space in the high shared arena for this process. This number does not indicate the largest single memory object that can be allocated, since the arena is probably fragmented.	Warp
29	QSV_MAXPROCESSES	Maximum number of concurrent processes supported.	Warp
30	QSV_VIRTUALADDRESSLIMIT	Size of the user's address space in MB.	Warp

Note

Major, minor and revision numbers for versions of OS/2 operating system are described below:

┌──────────┬──────────┬──────────┬──────────┐
│          │Major     │Minor     │Revision  │
├──────────┼──────────┼──────────┼──────────┤
│OS/2 2.0  │20        │00        │0         │
├──────────┼──────────┼──────────┼──────────┤
│OS/2 2.1  │20        │10        │0         │
├──────────┼──────────┼──────────┼──────────┤
│OS/2 2.11 │20        │11        │0         │
├──────────┼──────────┼──────────┼──────────┤
│OS/2 3.0  │20        │30        │0         │
├──────────┼──────────┼──────────┼──────────┤
│OS/2 4.0  │20        │40        │0         │
└──────────┴──────────┴──────────┴──────────┘

An application can specify file objects managed by an installable file system that supports long file names. Because some installable file systems support longer names than others, the application should issue DosQuerySysInfo upon initialization.

DosQuerySysInfo returns the maximum path length (QSV_MAX_PATH_LENGTH) supported by the installed file system. The path length includes the drive specifier (d:), the leading backslash ( \ ), and the trailing null character. The value returned by DosQuerySysInfo can be used to allocate buffers for path names returned by other functions.

Since memory usage in the system changes constantly, the values returned by QSV_MAXHPRMEM and QSV_MAXHSMMEM should only be used as an indication of current memory usage.

Returns

rc (APIRET) - returns

Indicates if any error occurred.

0	NO_ERROR
87	ERROR_INVALID_PARAMETER
111	ERROR_BUFFER_OVERFLOW

Include Info

#define INCL_DOSMISC
#include <os2.h>

Usage Explanation

DosQuerySysInfo queries different information about the system. and returns it in a buffer sent to it with the call.

Sample Code

Declaration:

1. define INCL_DOSMISC
2. include <os2.h>

ULONG iStart; /* Ordinal of the first system variable to return. */ ULONG iLast; /* Ordinal of the last system variable to return. */ PVOID pBuf; /* Address of the data buffer where the system returns the variable values. */ ULONG cbBuf; /* Length, in bytes, of the data buffer. */ APIRET ulrc; /* Return Code. */

ulrc = DosQuerySysInfo(iStart, iLast, pBuf, cbBuf);

Sample:

ULONG aulBuffer[4];
APIRET rc;

rc = DosQuerySysInfo(QSV_VERSION_MAJOR, QSV_MS_COUNT,
		     (void *)aulBuffer, 4*sizeof(ULONG));
if(rc) {
  printf("Error! DosQuerySysInfo returned %d.\n",rc);
  return(-1);
}
else {
  printf("You are running version %d.%d revision %c.\n",
          aulBuffer[0], aulBuffer[1], (char) aulBuffer[2]);
  printf("Your system has been running %d hour(s) and %d minute(s).\n",
          aulBuffer[3]/3600000, (aulBuffer[3]%3600000)/60000);
}

This example queries and displays the maximum length for a path name and the total amount of physical memory in bytes.

#define INCL_DOSMISC       /* DOS Miscellaneous values */
#define INCL_DOSERRORS     /* DOS Error values         */
#include <os2.h>
#include <stdio.h>

int main(VOID)  {

  ULONG   aulSysInfo[QSV_MAX] = {0};       /* System Information Data Buffer */
  APIRET  rc                  = NO_ERROR;  /* Return code                    */

  rc = DosQuerySysInfo(1L,                 /* Request all available system   */
                       QSV_MAX,            /* information                    */
                       (PVOID)aulSysInfo,
                       sizeof(ULONG)*QSV_MAX);

  if (rc != NO_ERROR) {
     printf("DosQuerySysInfo error: return code = %u\n", rc);
     return 1;
  } else {
     printf("Maximum length for a path name is %u characters.\n",
             aulSysInfo[QSV_MAX_PATH_LENGTH-1]);  /* Max length of path name */

     printf("Total physical memory is %u bytes.\n",
             aulSysInfo[QSV_TOTPHYSMEM-1]);       /* Total physical memory   */
  } /* endif */

   return NO_ERROR;
}

Related Functions

• DosCreateDir
• DosFindFirst
• DosFindNext
• DosOpen
• DosQueryCurrentDir
• DosQueryFSInfo
• DosQueryPathInfo
• DosSearchPath
• DosSetCurrentDir
• DosSetPathInfo
• DosSetFSInfo