isatty (BPX1ITY) (POSIX Version) — Determine whether a file descriptor represents a terminal
Function
The isatty callable service determines whether a file is a terminal.
Requirements
| Operation | Environment |
|---|---|
| Authorization: | Supervisor state or problem state, any PSW key |
| Dispatchable unit mode: | Task |
| Cross memory mode: | PASN = HASN |
| AMODE: | 31-bit |
| ASC mode: | Primary mode |
| Interrupt status: | Enabled for interrupts |
| Locks: | Unlocked |
| Control parameters: | All parameters must be addressable by the caller and in the primary address space. |
Format
The syntax format is as
follows:
CALL BPX1ITY,(File_descriptor,
Return_value)Parameters
- File_descriptor
- Supplied parameter
- Type:
- Integer
- Length:
- Fullword
The name of a fullword containing the file descriptor.
- Return_value
- Returned parameter
- Type:
- Integer
- Length:
- Fullword
The name of a fullword in which the isatty service returns
1if File_descriptor is a terminal, or0if it is not a terminal.
Usage notes
This function does not return
-1. If the file descriptor is not valid, a zero is
returned. If this service fails for other reasons, the process abends.
Related services
Characteristics and restrictions
There are no restrictions on the use of the isatty service.