Tests a file descriptor.
Standard C Library (libc.a)
int isastream(int fildes);
The isastream subroutine determines if a file descriptor represents a STREAMS file.
| Item | Description |
|---|---|
| fildes | Specifies which open file to check. |
On successful completion, the isastream subroutine returns a value of 1 if the fildes parameter represents a STREAMS file, or a value of 0 if not. Otherwise, it returns a value of -1 and sets the errno global variable to indicate the error.
If unsuccessful, the errno global variable is set to the following value:
| Value | Description |
|---|---|
| EBADF | The fildes parameter does not specify a valid open file. |