BBS: Inland Empire Archive Date: 02-16-94 (16:03) Number: 155 From: GARY GLUECKERT Refer#: 136 To: FLOYD HOBSON Recvd: NO Subj: Re: Get dos errorlevel Conf: (2) Quik_Bas
FH>check for the errorlevel<G>. There doesn't appear to be a clean way FH>to do this - my workaroud has been to call the child via a batch file FH>that creates a nul length semaphore file to reflect the error level, FH>then delete the nul file after determining the error level. I found a public domain ASM object file that can be linked into QB4.x, BASIC 7.x programs which does this so now we can go and do it cleanly <g>. If you study the code below you will see how it's done and perhaps you can write the Int calls in BASIC (but why bother if they are in ASM). ; MonitorShell (MONSHELL.ASM) ; Written by Tony Elliott ; EllTech Development, Inc. ; 4374 Shallowford Industrial Parkway ; Marietta, GA 30066 ; (404) 928-8960 Voice or (404) 928-7111 BBS (HST) ; Released into the public domain. ; This routine is written for Microsoft QuickBASIC 4.x, BASIC 6.x and Microsoft ; PDS 7.x. Assemble using MASM 5.1: MASM MONSHELL; ; You can link it directly to your program, place it in a LINK library (.LIB) ; or a .QLB. ; To use it: ; DECLARE SUB MonitorShell () ; DECLARE FUNCTION FetchErrorLevel% () ; ; CALL MonitorShell ; SHELL "PkZip -Xxy" ; PRINT "ErrorLevel returned from SHELL:";FetchErrorLevel .model medium, basic .code Old21 Label Dword ;Label pointing to old Int 21h handler Old21Offset dw ? ;Offset part Old21Segment dw ? ;Segment part MonitorSet db 0 ;Our "hooked" flag ExitCode db ? ;Where we store the exit code MonitorShell proc uses ds ; From BASIC: CALL MonitorShell cmp cs:MonitorSet,0 ;Are we already hooked? jnz MonitorExit ;If so, exit mov ax,3521h ;Get current vector for int 21h int 21h mov cs:Old21Segment,es ;Remember it for later mov cs:Old21Offset,bx mov ax,2521h push cs pop ds ;Point int 21h handler to our code mov dx, offset OurInt21 int 21h mov cs:MonitorSet,-1 ;Set our flag MonitorExit: ret OurInt21: ;Our Int 21h handler cmp ah,4ch ;Is it a 'terminate' request? jnz Continue ;If not, continue on mov cs:ExitCode,al ;Remember the exit code push ax push ds mov ax,2521h ;Unhook ourself after the first hit mov ds,Old21Segment mov dx,Old21Offset int 21h ;Point Int 21h back to original handler pop ds pop ax mov cs:MonitorSet,0 ;Set out flag back to zero Continue: jmp dword ptr [Old21] ;Transfer control to original Int 21h MonitorShell endp FetchErrorLevel proc ;From BASIC: DECLARE FUNCTION FetchErrorLevel% ; PRINT "Last errorlevel:"; FetchErrorLevel% mov al,cs:ExitCode ;Put the errorlevel into al xor ah,ah ;Zero ah ret ;ErrorLevel returned as result FetchErrorLevel endp end If you don't have the MASM compiler to create the .OBJ file you can FREQ the entire package from 1:107/270 with the magic name MONSHELL, This goes for all others... help yourself. Thanks to Tony Elliott for this great little helper! Gary $$55 --- QScan v1.06b * Origin: * Wingit! * Tallahassee, Fl * (904) 386-8693 (1:3605/13)
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