This is part of Family API which allow to create dual-os version of program runs under OS/2 and DOS

Note: This is legacy API call. It is recommended to use 32-bit equivalent

DosGetEnv

This call returns the address of the process environment string for the current process.

Syntax

DosGetEnv (EnvSegment, CmdOffset)

Parameters

;EnvSegment (PSEL) - output : Address of the selector for the environment segment. ;CmdOffset (PUSHORT) - output : Address of the offset to the command line within the environment segment.

Return Code

;rc (USHORT) - return:Return code descriptions are: * 0 NO_ERROR * 12 ERROR_INVALID_ACCESS

Remarks

DosGetEnv can be used by dynamic link library routines that need to determine the environment for the current process.

When a process issues DosExecPgm to start another process, the program that receives control is returned a pointer to the environment segment.

Bindings

C Binding

<PRE> #define INCL_DOSMISC

USHORT rc = DosGetEnv(EnvSegment, CmdOffset);

PUSHORT EnvSegment; /* Selector (returned) */ PUSHORT CmdOffset; /* Command line offset (returned) */

USHORT rc; /* return code */ </PRE>

MASM

<PRE> EXTRN DosGetEnv:FAR INCL_DOSMISC EQU 1

PUSH@ WORD EnvSegment ;Selector (returned) PUSH@ WORD CmdOffset ;Command line offset (returned) CALL DosGetEnv

Returns WORD </PRE>

Example Code

The following example shows how one may obtain information for program initialization. The program locates the environment segment and prints the name of the command from the command line. It then obtains the OS/2 version number and prints it. <PRE> #define INCL_DOS #include <os2.h> #define ENVVARNAME “PATH”

main() {

SEL EnvSel; /* Environment segment selector (returned) */
USHORT CmdOffset; /* Offset into env. seg. of command line (returned) */
PSZ FAR *Commandline; /* Pointer made by EnvSel and CmdOffset */
USHORT Version; /* Version numbers (returned) */
BYTE MajorVer; /* Major version number */
BYTE MinorVer; /* Minor version number */
USHORT rc; /* return code */

/** Locate environment segment and offset of command line. **/
if(!(rc=DosGetEnv(&EnvSel, /* Env. seg. selector (returned) */
&CmdOffset))) /* Offset of command line (returned) */
printf("Environment located; selector is %x offset is %x\n", EnvSel,
CmdOffset);

/** Use a macro to make a far pointer out of selector:offset pair. **/
/** Notice the far-string pointer specification (%Fs) used to print **/

Commandline = MAKEP(EnvSel, CmdOffset);
printf("Command entered is %Fs.\n", Commandline);

/** Obtain and print version info; use macros to extract info. **/
/** We need to divide by 10 to obtain true version numbers. **/

if(!(rc=DosGetVersion(&Version)))
{
MajorVer = HIBYTE(Version) / 10;
MinorVer = LOBYTE(Version) / 10;
printf("This is OS/2 version %d.%d\n", MajorVer, MinorVer);
}

} </PRE>

Note

Text based on http://www.edm2.com/index.php/DosGetEnv

Family API
DOS	Process Manager	DosBeep DosExit DosSleep DosExecPgm
File Manager	DosChDir DosChgFilePtr DosClose DosDelete DosDupHandle DosMkDir DosMove DosQCurDir DosQCurDisk DosSetFileMode DosOpen DosQFileInfo DosRead DosQFileMode DosQFSInfo DosQVerify DosRmDir DosSelectDisk DosFindClose DosFindFirst DosFindNext DosSetFileInfo DosSetVerify DosWrite DosFileLocks DosSetFHandState DosNewSize DosBufReset DosQFHandState DosSetFSinfo DosShutdown
Memory Manager	DosFreeSeg DosSubAlloc DosSubFree DosSubSet DosAllocHuge DosAllocSeg DosReallocHuge DosReallocSeg DosGetHugeShift DosCreateCSAlias
NLS	DosCaseMap DosGetCtryInfo DosGetDBCSEv DosSetCtryCode DosGetCollate DosGetMessage DosInsMessage DosPutMessage
Date and Time	DosSetDateTime DosGetDateTime
Devices	DosDevConfig DosDevIOCtl DosDevIOCtl2
Signals	DosHoldSignal DosSetSigHandler
Misc	BadDynLink DosGetEnv DosGetMachineMode DosGetVersion DosError DosErrClass DosSetVec
KBD	KbdCharIn KbdFlushBuffer KbdGetStatus KbdSetStatus KbdStringIn KbdPeek
VIO	VioGetBuf VioGetConfig VioGetCurPos VioGetCurType VioGetPhysBuf VioReadCellStr VioReadCharStr VioScrollUp VioScrollDn VioScrollLf VioScrollRt VioScrUnLock VioSetCurPos VioSetCurType VioSetMode VioGetMode VioShowBuf VioWrtCellStr VioWrtCharStr VioWrtCharStrAtt VioWrtNAttr VioWrtNCell VioWrtNChar VioWrtTTY VioScrLock VioPopUp
Tools	BIND
Modules	DOSCALLS.DLL VIOCALLS.DLL KBDCALLS.DLL MSG.DLL
Libraries	API.LIB OS2386.LIB FAPI.LIB DOSCALLS.LIB SUBCALLS.LIB