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CPM OPERATING SYSTEMS/CPM 68K/1.0X SOURCES/v102a/clib/open.c

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+/****************************************************************************
+*
+*		   C   F I L E   O P E N   R O U T I N E
+*		   -------------------------------------
+*	Copyright 1982 by Digital Research Inc.  All rights reserved.
+*
+*	The "open" routine opens a "C" file and returns a file id. 
+*	Comes in 3 flavors, one for ascii, one for binary, and the default
+*	(currently to ascii).
+*
+*	Calling Sequence:
+*		fid = open(fname,mode)
+*		fid = opena(fname,mode)
+*		fid = openb(fname,mode)
+*		fid = _open(fname,mode,type);
+*
+*	Where:
+*		fname	is the address of a null terminated file name.
+*		mode	is the open mode:
+*				0 => READ access only
+*				1 => WRITE access only
+*				2 => Both READ and WRITE
+*		type	is 0 for ASCII files, 1 for BINARY
+*
+*
+*****************************************************************************/
+#include	"portab.h"			/* 			    */
+#include	"osif.h"			/* 			    */
+#include 	"osiferr.h"			/*			    */
+#include	"errno.h"			/*			    */
+EXTERN	BYTE	__tname[];			/* -> Terminal name	    */
+EXTERN	BYTE	__lname[];			/* -> List device name	    */
+
+WORD	_open (fname,mode,xtype)		/****************************/
+	BYTE	*fname;				/* -> File name		    */
+	WORD	mode;				/* Open mode		    */
+	WORD	xtype;				/* File type		    */
+{						/****************************/
+	REG  WORD	ich;			/* Channel number for open  */
+	REG  FD		*ch;			/* -> CCB for channel	    */
+						/*			    */
+	if((ich = _allocc()) == FAILURE)	/* Allocate a channel	    */
+		return(FAILURE);		/*	Can't: EMFILE	    */
+						/*			    */
+	__chinit(ich);				/* Clear out channel's ccb  */
+	ch = _getccb(ich);			/* Get address of ccb	    */
+						/*			    */
+	if(mode == READ)			/* 	 If read only,	    */
+		ch -> flags |= ISREAD;		/*	    set READONLY bit*/
+	if(xtype == 0)				/* Is ASCII file?	    */
+		ch -> flags |= ISASCII;		/*	Yes, mark it	    */
+						/*			    */
+	if(_strcmp(fname,__tname) == 0)		/* if a terminal	    */
+	{					/* 			    */
+	  ch->flags |= ISTTY|OPENED;		/* mark as tty		    */
+	  return(ich);				/* Return file descriptor   */
+	}					/****************************/
+	else if(_strcmp(fname,__lname) == 0)	/* List device?		    */
+	{					/*			    */
+	  ch->flags |= ISLPT|OPENED;		/* Mark as printer	    */
+	  return(ich);				/* Return file descriptor   */
+	}					/*			    */
+						/****************************/
+	if(__open(ich,fname,OPEN) != 0)		/* Use POS SVC interface    */
+	{					/*			    */
+		_freec(ich);			/* deallocate channel       */
+		RETERR(FAILURE,ENOENT);		/* If return <> 0, NFG.	    */
+	}					/****************************/
+						/* Else:		    */
+	ch -> flags |= OPENED;			/*	 Set OPEN bit	    */
+	lseek(ch->chan, 0L, 2);			/*       Kludge to set      */
+	lseek(ch->chan, 0L, 0);			/*       hi water mark      */
+	return(ich);				/*	 Return Channel #   */
+}						/****************************/
+
+WORD	open(fname,mode)			/* CLEAR FUNCTION ***********/
+	BYTE *fname; WORD mode;
+{	return(_open(fname,mode,0));	}	/* default to ascii	    */
+
+WORD	opena(fname,mode)			/* CLEAR FUNCTION ***********/
+	BYTE *fname; WORD mode;
+{	return(_open(fname,mode,0));	}	/* open ascii file	    */
+
+WORD	openb(fname,mode)			/* CLEAR FUNCTION ***********/
+	BYTE *fname; WORD mode;
+{	return(_open(fname,mode,1));	}	/* open binary file	    */