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* manual/intro.texi: Document safety identifiers and

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conditionals.
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Alexandre Oliva 2014-02-01 03:48:32 -02:00
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@ -1,3 +1,8 @@
2014-02-01 Alexandre Oliva <aoliva@redhat.com>
* manual/intro.texi: Document safety identifiers and
conditionals.
2014-02-01 Alexandre Oliva <aoliva@redhat.com>
* manual/string.texi (wcstok): Fix prototype.

48
manual/intro.texi
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@ -669,7 +669,10 @@ concurrent and reentrant interactions with it, by not using it in signal
handlers or blocking signals that might use it, and holding a lock while
calling these functions and interacting with the terminal. This lock
should also be used for mutual exclusion with functions marked with
@code{@mtasurace{:tcattr}}.
@code{@mtasurace{:tcattr(fd)}}, where @var{fd} is a file descriptor for
the controlling terminal. The caller may use a single mutex for
simplicity, or use one mutex per terminal, even if referenced by
different file descriptors.
Functions marked with @code{term} as an AC-Safety issue are supposed to
restore terminal settings to their original state, after temporarily
@ -698,7 +701,6 @@ taken into account in certain classes of programs:
@itemize @bullet
@c revisit: uses are mt-safe, distinguish from const:locale
@item @code{locale}
@cindex locale
@ -729,7 +731,6 @@ constant in these contexts, which makes the former safe.
@c because of the unexpected locale changes.
@c revisit: this was incorrectly used as an mt-unsafe marker.
@item @code{env}
@cindex env
@ -855,6 +856,47 @@ properties we documented are identical to those mandated by POSIX for
the corresponding functions.
@item @code{:identifier}
@cindex :identifier
Annotations may sometimes be followed by identifiers, intended to group
several functions that e.g. access the data structures in an unsafe way,
as in @code{race} and @code{const}, or to provide more specific
information, such as naming a signal in a function marked with
@code{sig}. It is envisioned that it may be applied to @code{lock} and
@code{corrupt} as well in the future.
In most cases, the identifier will name a set of functions, but it may
name global objects or function arguments, or identifiable properties or
logical components associated with them, with a notation such as
e.g. @code{:buf(arg)} to denote a buffer associated with the argument
@var{arg}, or @code{:tcattr(fd)} to denote the terminal attributes of a
file descriptor @var{fd}.
The most common use for identifiers is to provide logical groups of
functions and arguments that need to be protected by the same
synchronization primitive in order to ensure safe operation in a given
context.
@item @code{/condition}
@cindex /condition
Some safety annotations may be conditional, in that they only apply if a
boolean expression involving arguments, global variables or even the
underlying kernel evaluates evaluates to true. Such conditions as
@code{/hurd} or @code{/!linux!bsd} indicate the preceding marker only
applies when the underlying kernel is the HURD, or when it is neither
Linux nor a BSD kernel, respectively. @code{/!ps} and
@code{/one_per_line} indicate the preceding marker only applies when
argument @var{ps} is NULL, or global variable @var{one_per_line} is
nonzero.
When all marks that render a function unsafe are adorned with such
conditions, and none of the named conditions hold, then the function can
be regarded as safe.
@end itemize