SDGETV(S) UNIX System V SDGETV(S)
Name
sdgetv, sdwaitv - synchronizes shared data access
Syntax
#include <sys/sd.h>
int sdgetv(addr)
char *addr;
int sdwaitv(addr, vnum)
char *addr;
int vnum;
Description
sdgetv and sdwaitv may be used to synchronize cooperating
processes that are using shared data segments. The return
value of both routines is the version number of the shared
data segment attached to the process at address addr. The
version number of a segment changes whenever some process
does an sdleave for that segment.
sdgetv simply returns the version number of the indicated
segment.
sdwaitv forces the current process to sleep until the
version number for the indicated segment is no longer equal
to vnum.
Return Value
Upon successful completion, both sdgetv and sdwaitv return a
positive integer that is the current version number for the
indicated shared data segment. Otherwise, a value of -1 is
returned, and errno is set to indicate the error.
See Also
sdenter(S), sdget(S)
Notes
This routine must be linked using the linker option -lx.
(printed 6/20/89)