Added seek.c, an interface to the lseek systemcall

modules/src/system/.distr

@@ -17,3 +17,4 @@ system.h
 time.c
 unlock.c
 write.c
+seek.c

modules/src/system/Makefile

@@ -7,10 +7,10 @@ INCLUDES = -I.
 CFLAGS	= $(INCLUDES) -O
 OBJ	= access.o break.o chmode.o close.o create.o filesize.o \
 	modtime.o lock.o open.o read.o remove.o stop.o \
-	system.o time.o unlock.o write.o
+	system.o time.o unlock.o write.o seek.o
 CSRC	= access.c break.c chmode.c close.c create.c filesize.c \
 	modtime.c lock.c open.c read.c remove.c stop.c \
-	system.c time.c unlock.c write.c
+	system.c time.c unlock.c write.c seek.c
 SRC	= Makefile system.h $(CSRC)
 
 all:		$(LIBSYS)

modules/src/system/seek.c

@@ -0,0 +1,18 @@
+/*
+ * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
+ * See the copyright notice in the ACK home directory, in the file "Copyright".
+ */
+/* $Header$ */
+
+#include <system.h>
+
+long lseek();
+
+int
+sys_seek(fp, off, whence, poff)
+	File *fp;
+	long off;
+	long *poff;
+{
+	return (*poff = lseek(fp->o_fd, off, whence)) >= 0;
+}

modules/src/system/system.3

@@ -29,6 +29,12 @@ sys_break, sys_stop, sys_time \- system call interface
 .B char *bufptr;
 .B int nbytes;
 .PP
+.B int sys_seek(filep, offset, whence, poffset)
+.B File *filep;
+.B long offset;
+.B int whence;
+.B long *poffset;
+.PP
 .B int sys_reset(filep)
 .B File *filep
 .PP
@@ -142,6 +148,31 @@ A non-zero return value indicates that
 .I nbytes
 are actually written.
 .PP
+.I Sys_seek
+sets the file pointer of
+.I filep
+as follows:
+.IP " "
+If
+.I whence
+is 0, the pointer is set to
+.I offset
+bytes.
+.IP " "
+If
+.I whence
+is 1, the pointer is set to its current location plus
+.IR offset .
+.IP " "
+If
+.I whence
+is 2, the pointer is set to the size of the file plus
+.IR offset .
+.PP
+Upon succesful completion, the resulting pointer location is returned in
+.IR poffset ,
+and 1 is returned. Otherwise, 0 is returned.
+.PP
 .I Sys_reset
 causes the open file known by
 .I filep