Guardian C Library Calls Reference Manual

__ns_fget_file_open_state (supplementary)
3-128 128833—Guardian TNS C Library Calls Reference Manual
Reference to Library Calls
__ns_fget_file_open_state (supplementary)
The __ns_fget_file_open_state function returns the file open state information for a file
open for ANSI I/O.
stream
denotes a file opened for ANSI I/O.
file_open_state
points to a variable that stores the file open state information.
Return Value
0 if the operation is successful, -1 if an error occurs.
Usage Guidelines
•
This function is called from the primary process to retrieve the current file open state
information. The primary process sends the state information through the
$RECEIVE facility to the backup process. The backup process calls the
__ns_backup_fopen function to perform a backup open of the file.
•
The variable containing the file state information, not the pointer to the variable,
must be sent through the $RECEIVE facility from the primary process to the backup
process.
•
If an error occurs, errno is set to one of the following:
•
ENONSTOP, if the file specified in the stream argument is not open.
•
A Guardian file system error code, if a file system error occurs.
•
The only meaningful operations on file open state information are retrieving with the
__ns_fget_file_open_state function, starting a backup file open with the
__ns_backup_fopen function, and copying with an assignment statement or a copy
function from the C run-time library. The results of manipulating components of the
file open state information are undefined.
•
In addition to either the CLARGE or CWIDE library file, you must bind the
CNONSTOP library file into programs that use this function.
•
This function can only be used in the Guardian environment.
•
Refer to the Guardian Programmer’s Guide for complete details on fault-tolerant
programming in C.
#include <nonstoph>
long __ns_fget_file_open_state(
FILE *stream,
__ns_std_io_file_open_state *file_open_state);