isatty (BPX2ITY, BPX4ITY) (X/Open 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 (BPX2ITY): | 31-bit |
| AMODE (BPX4ITY): | 64-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:
|
AMODE 64 callers use BPX4ITY with the same parameter.
Parameters
- File_descriptor
- Supplied parameter
- Type:
- Integer
- Length:
- Fullword
The name of a fullword that contains the file descriptor.
- Return_value
- Returned parameter
- Type:
- Integer
- Length:
- Fullword
The name of a fullword in which the isatty service returns 1 if File_descriptor is a terminal, or 0 if it is not a terminal.
- Return_code
- Returned parameter
- Type:
- Integer
- Length:
- Fullword
The name of a fullword in which the isatty service stores the return code. The isatty service may return Return_code only if Return_value is 0. See z/OS UNIX System Services Messages and Codes for a complete list of possible return code values. The isatty service can return one of the following values in the Return_code parameter:Return_code Explanation EBADF The filedes argument is not a valid open file descriptor. ENOTTY The filedes argument is not associated with a terminal. - Reason_code
- Returned parameter
- Type:
- Integer
- Length:
- Fullword
The name of a fullword in which the isatty service stores the reason code. The isatty service may return Reason_code only if Return_value is 0. Reason_code further qualifies the Return_code value. For the reason codes, see z/OS UNIX System Services Messages and Codes.
Usage notes
- This version of isatty is XPG4 compliant.
- This function does not return -1. If the file descriptor is not valid, a zero is returned.
Related services
Characteristics and restrictions
There are no restrictions on the use of the isatty service.
Examples
For an example using this callable service, see BPX2ITY (isatty) example.