Guardian Procedure Calls Reference Manual

AWAITIO[X|XL] Procedures
Summary
Syntax for C Programmers
Syntax for TAL Programmers
Parameters
Condition Code Settings
Returned Value
Operation and Completion Summary
Considerations
OSS Considerations
Related Programming Manual
Summary
The AWAITIO, AWAITIOX, and AWAITIOXL procedures are used to complete a previously initiated
I/O operation. Use AWAITIO with the 16-bit versions such as READ, WRITEREAD, and so forth.
Use AWAITIOX[L] with the extended 32-bit (or ‘X') versions of the I/O procedures such as READX,
WRITEREADX, and so forth.
Use AWAITIO[X|XL] to:
• Wait for the operation to complete on:
A particular file—Application process execution suspends until the completion occurs. A
timeout is considered to be a completion in this case.
◦
◦ Any file or for a timeout to occur—A timeout is not considered a completion in this case.
• Check for the operation to complete on:
A particular file—The call to AWAITIO[X|XL] immediately returns to the application
process, regardless of whether there is a completion or not. (If there is no completion, an
error indication is returned.)
◦
◦ Any file
If AWAITIO[X|XL] is used to wait for a completion, you can specify a time limit.
NOTE: The AWAITIOXL procedure is supported on systems running H06.18 and later H-series
RVUs and J06.07 and later J-series RVUs.
The AWAITIO[X|XL] procedures perform the same operation as the FILE_AWAITIO64_ Procedure
(page 353), which is recommended for new code.
Key differences in FILE_AWAITIO64_ are:
• The pointer and tag parameters are 64 bits wide.
• The timelimit parameter is 32 bits wide.
• The procedure returns an error code value rather than a condition code, simplifying
error-handling code.
76 Guardian Procedure Calls (A-B)