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:
CALL BPX2ITY,(File_descriptor,
Return_value,
Return_code,
Reason_code)
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, or0
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 is0
. For a list of return code values, see Return codes (errnos) in z/OS UNIX System Services Messages and Codes. 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 a list of reason codes, see Reason codes in 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.