2 Copyright 1988-2022 Free Software Foundation, Inc.
3 This is part of the GCC manual.
4 For copying conditions, see the copyright.rst file.
6 .. _ia-64-function-attributes:
8 IA-64 Function Attributes
9 ^^^^^^^^^^^^^^^^^^^^^^^^^
11 These function attributes are supported on IA-64 targets:
13 .. index:: syscall_linkage function attribute, IA-64
15 .. ia-64-fn-attr:: syscall_linkage
17 This attribute is used to modify the IA-64 calling convention by marking
18 all input registers as live at all function exits. This makes it possible
19 to restart a system call after an interrupt without having to save/restore
20 the input registers. This also prevents kernel data from leaking into
23 .. index:: version_id function attribute, IA-64
25 .. ia-64-fn-attr:: version_id
27 This IA-64 HP-UX attribute, attached to a global variable or function, renames a
28 symbol to contain a version string, thus allowing for function level
29 versioning. HP-UX system header files may use function level versioning
30 for some system calls.
34 extern int foo () __attribute__((version_id ("20040821")));
36 Calls to ``foo`` are mapped to calls to ``foo{20040821}``.