Hello Przemek
Next applicantion instance is put under
indefinite loop in dbUseArea() if a table is
attempted to be opened in EXCLUSIVE mode where
first instance has alreay that table open in
SHARED mode. Appln is compiled with MT support.
Here is the code from my appln ( working since
good old Clipper days )
function Sema4Init()
local fname := if( SetCache(), SEMA4FILE , SEMA4PATH+'\'+SEMA4FILE )
local iName := if( SetCache(), SEMA4INDEX, SEMA4PATH+'\'+SEMA4INDEX )
if !VouExistTable( SEMA4ALIAS, SEMA4FILE, SEMA4PATH, cSemaDrv, .f. )
bDbCreate( fName,{ { 'sema4name','C',20,0 },{ 'username','C',5,0 } },
cSemaDrv )
if !VouExistTable( SEMA4ALIAS, SEMA4FILE, SEMA4PATH, cSemaDrv,.f. )
alert( 'SemaPhore file could not be created' )
return .f.
endif
endif
// check if anybody is logged with exclusive use
//
// ///////////// NEXT INSTANCE HANGS HERE ( CPU USAGE 50% FOR THIS
INSTANCE ) ////////
//
if eval( {|| dbUseArea( .t.,cSemaDrv,fName,SEMA4ALIAS,.f. ), !NetErr() }
)
// other code
DbCloseArea()
endif
// compulsory use sema4 in shared mode
do while .t.
if eval( {|| dbusearea(.t.,cSemaDrv,fName,SEMA4ALIAS,.T.),!netErr()} )
if !VouExistIndex( SEMA4ALIAS, SEMA4INDEX, SEMA4PATH, cSemaDrv, .f.
)
dbclosearea()
return .f.
endif
ordlistclear()
ordlistadd( iName )
ordsetfocus( 1 )
else
return .f.
endif
exit
enddo
do while !dbRelease( SEMA4ALIAS ) //////////////// NOTE, may be
important ////////////
enddo
return .t.
//----------------------------------------------------------------------//
Regards
Pritpal Bedi
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