ftok [ MPE/iX Developer's Kit Reference Manual Volume II ] MPE/iX 5.0 Documentation
MPE/iX Developer's Kit Reference Manual Volume II
ftok
Returns a key used in calls to msgget(), semget(), and shmget() function
calls.
Syntax
#include <sys/types.h>
#include <sys/ipc.h>
key_t ftok (char *pathname, char id);
Parameters
pathname Passes a pointer to a string containing the pathname of a file
accessible to the calling process.
id Passes a character used to further qualify the returned key.
Return Values
!=-1 Key value returned.
-1 Error. The specified pathname does not exist or is not
accessible to the calling process.
Description
[REV BEG]
The ftok() function can be used to return a key based on both pathname
and id. This key [REV END]can be used in subsequent calls to the SVID
IPC msgget(), semget(), and shmget() functions.
A different key is returned when called with the same pathname but a
different character is passed in id.
Implementation Considerations
None.
Errors
If an error occurs, errno is set to the following value.
EINVAL CAUSE The pathname parameter points to an invalid address,
or pathname specifies a nonexistent file, or the
caller does not have the correct access to the
pathname.
ACTION Make sure that pathname points to a valid and
existing pathname to which the caller has access.
See Also
msgget(), semget(), shmget()
MPE/iX 5.0 Documentation