DosQuerySysInfo returns a single system variable or a range of system variables to a user-allocated buffer. To request a single system variable, set iStart equal to iLast. To request a range of system variables, set iStart less than iLast.

Each system variable is a ULONG value. The following list gives the ordinal index, name, and description of the system variables.

• QSV_MAX_PATH_LENGTH
  Maximum length, in bytes, of a path name.

• QSV_MAX_TEXT_SESSIONS
  Maximum number of text sessions.

• QSV_MAX_PM_SESSIONS
  Maximum number of PM sessions.

• QSV_MAX_VDM_SESSIONS
  Maximum number of DOS sessions.

• QSV_BOOT_DRIVE
  Drive from which the system was started (1 means drive A, 2 means drive B, and so on).

• QSV_DYN_PRI_VARIATION
  Dynamic priority variation flag (0 means absolute priority, 1 means dynamic priority).

• QSV_MAX_WAIT
  Maximum wait in seconds.

• QSV_MIN_SLICE
  Minimum time slice in milliseconds.

• QSV_MAX_SLICE
  Maximum time slice in milliseconds.

  10

  QSV_PAGE_SIZE
  Memory page size in bytes. This value is 4096 for the 80386 processor.
  11
  QSV_VERSION_MAJOR
  Major version number (see note below).
  12
  QSV_VERSION_MINOR
  Minor version number (see note below).
  13
  QSV_VERSION_REVISION
  Revision number (see note below).
  14
  QSV_MS_COUNT
  Value of a 32-bit, free-running millisecond counter. This value is zero when the system is started.
  15
  QSV_TIME_LOW
  Low-order 32 bits of the time in seconds since January 1, 1970 at 0:00:00.
  16
  QSV_TIME_HIGH
  High-order 32 bits of the time in seconds since January 1, 1970 at 0:00:00.
  17
  QSV_TOTPHYSMEM
  Total number of bytes of physical memory in the system.
  18
  QSV_TOTRESMEM
  Total number of bytes of resident memory in the system.
  19
  QSV_TOTAVAILMEM
  Maximum number of bytes of memory that can be allocated by all processes in the system. This number is advisory and is not guaranteed, since system conditions change constantly.
  20
  QSV_MAXPRMEM
  Maximum number of bytes of memory that this process can allocate in its private arena. This number is advisory and is not guaranteed, since system conditions change constantly.
  21
  QSV_MAXSHMEM
  Maximum number of bytes of memory that a process can allocate in the shared arena. This number is advisory and is not guaranteed, since system conditions change constantly.
  22
  QSV_TIMER_INTERVAL
  Timer interval in tenths of a millisecond.
  23
  QSV_MAX_COMP_LENGTH
  Maximum length, in bytes, of one component in a path name.
  24
  QSV_FOREGROUND_FS_SESSION
  Session ID of the current foreground full-screen session. Note that this only applies to full-screen sessions. The Presentation Manager session (which displays Vio-windowed, PM, and windowed DOS Sessions) is full-screen session ID 1.
  25
  QSV_FOREGROUND_PROCESS
  Process ID of the current foreground process.

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

  ÚÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄ¿³          ³Major     ³Minor     ³Revision  ³
  ÃÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄ´
  ³OS/2 2.0  ³20        ³00        ³0         ³
  ÃÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄ´
  ³OS/2 2.1  ³20        ³10        ³0         ³
  ÃÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄ´
  ³OS/2 2.11 ³20        ³11        ³0         ³
  ÃÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄ´
  ³OS/2 3.0  ³20        ³30        ³0         ³
  ÃÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄ´
  ³OS/2 4.0  ³20        ³40        ³0         ³
  ÀÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÙ
  

  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, for example, DosFindFirst and DosFindNext.

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