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EnigmA Amiga Run 1996 July
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EnigmA AMIGA RUN 09 (1996)(G.R. Edizioni)(IT)[!][issue 1996-07 & 08][EARSAN CD VIII].iso
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earcd
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util3
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fiflb382.lha
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lib.c
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1996-05-13
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124 lines
/*
* LIB.C
*
* Basic Library Resource Handling
*
* NOTE: all data declarations should be initialized since we skip
* normal C startup code (unless initial value is don't care)
*/
#include "defs.h"
#ifndef _DCC
extern const LONG (*Vectors[])(); /* Assembler library entry points */
#else
extern LONG Vectors(); /* trick a reference in the code section */
/* __far would require the registered DICE */
#endif
/* Avoid initializations so we save a data segment */
long SegList;
#ifdef _DCC /* work around pc-relative bug in DICE-2.06.xx */
ExecBase * SysBase = NULL;
#else
ExecBase * SysBase;
#endif
List FifoList;
/*
* The Initialization routine is given only a seglist pointer. Since
* we are NOT AUTOINIT we must construct and add the library ourselves
* and return either NULL or the library pointer. Exec has Forbid()
* for us during the call.
*
* If you have an extended library structure you must specify the size
* of the extended structure in MakeLibrary().
*/
LibCall Library *
LibInit(long segment)
{
Library *lib;
SysBase = *((ExecBase **) 4L);
if ((lib = MakeLibrary(Vectors,NULL,NULL,sizeof(Library),NULL))) {
lib->lib_Node.ln_Type = NT_LIBRARY;
lib->lib_Node.ln_Name = (char *)LibName;
lib->lib_Flags = LIBF_CHANGED|LIBF_SUMUSED;
lib->lib_Version = 38;
lib->lib_Revision = 2;
lib->lib_IdString = (APTR)LibId;
SegList = segment;
AddLibrary(lib);
NewList((MaxList *)&FifoList);
}
return(lib);
}
/*
* We expunge the library and return the Seglist ONLY if the open count
* is zero. If the open count is not zero we set the DELAYED-EXPUNGE
* flag and return NULL.
*
* Exec has Forbid() for us during the call. NOTE ALSO that Expunge
* might be called from the memory allocator and thus we CANNOT DO A
* Wait() or otherwise take a long time to complete (straight from RKM).
*
* Apparently RemLibrary(lib) calls our expunge routine and would
* therefore freeze if we called it ourselves. As far as I can tell
* from RKM, LibExpunge(lib) must remove the library itself as shown
* below.
*/
LibCall long
LibExpunge(long dummy, Library *lib)
{
if (lib->lib_OpenCnt) {
lib->lib_Flags |= LIBF_DELEXP;
return(NULL);
}
Remove((MaxNode *)lib);
FreeMem((void *)lib-lib->lib_NegSize, lib->lib_NegSize+lib->lib_PosSize);
return(SegList);
}
/*
* Open is given the library pointer and the version request. Either
* return the library pointer or NULL. Remove the DELAYED-EXPUNGE flag.
* Exec has Forbid() for us during the call.
*/
LibCall Library *
LibOpen(long version, Library *lib)
{
++lib->lib_OpenCnt;
lib->lib_Flags &= ~LIBF_DELEXP;
return(lib);
}
/*
* Close is given the library pointer and the version request. Be sure
* not to decrement the open count if already zero. If the open count
* is or becomes zero AND there is a LIBF_DELEXP, we expunge the library
* and return the seglist. Otherwise we return NULL.
*
* Note that this routine never sets LIBF_DELEXP on its own.
*
* Exec has Forbid() for us during the call.
*/
LibCall long
LibClose(long dummy, Library *lib)
{
if (lib->lib_OpenCnt && --lib->lib_OpenCnt)
return(NULL);
if (lib->lib_Flags & LIBF_DELEXP)
return(LibExpunge(0, lib));
return(NULL);
}