diff options
Diffstat (limited to 'man7/signal-safety.7')
| -rw-r--r-- | man7/signal-safety.7 | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/man7/signal-safety.7 b/man7/signal-safety.7 index 4bcb478..d307dda 100644 --- a/man7/signal-safety.7 +++ b/man7/signal-safety.7 @@ -3,7 +3,7 @@ .\" .\" SPDX-License-Identifier: Linux-man-pages-copyleft .\" -.TH signal-safety 7 2023-02-05 "Linux man-pages 6.05.01" +.TH signal-safety 7 2023-10-31 "Linux man-pages 6.7" .SH NAME signal-safety \- async-signal-safe functions .SH DESCRIPTION @@ -15,13 +15,13 @@ Many functions are async-signal-safe. In particular, nonreentrant functions are generally unsafe to call from a signal handler. -.PP +.P The kinds of issues that render a function unsafe can be quickly understood when one considers the implementation of the .I stdio library, all of whose functions are not async-signal-safe. -.PP +.P When performing buffered I/O on a file, the .I stdio functions must maintain a statically allocated data buffer @@ -38,7 +38,7 @@ the program is interrupted by a signal handler that also calls then the second call to .BR printf (3) will operate on inconsistent data, with unpredictable results. -.PP +.P To avoid problems with unsafe functions, there are two possible choices: .IP (a) 5 Ensure that @@ -50,26 +50,26 @@ with respect to global variables in the main program. Block signal delivery in the main program when calling functions that are unsafe or operating on global data that is also accessed by the signal handler. -.PP +.P Generally, the second choice is difficult in programs of any complexity, so the first choice is taken. -.PP +.P POSIX.1 specifies a set of functions that an implementation must make async-signal-safe. (An implementation may provide safe implementations of additional functions, but this is not required by the standard and other implementations may not provide the same guarantees.) -.PP +.P In general, a function is async-signal-safe either because it is reentrant or because it is atomic with respect to signals (i.e., its execution can't be interrupted by a signal handler). -.PP +.P The set of functions required to be async-signal-safe by POSIX.1 is shown in the following table. The functions not otherwise noted were required to be async-signal-safe in POSIX.1-2001; the table details changes in the subsequent standards. -.PP +.P .TS lb lb l l. @@ -272,7 +272,7 @@ T} \fBwmemset\fP(3) Added in POSIX.1-2008 TC2 \fBwrite\fP(2) .TE -.PP +.P Notes: .IP \[bu] 3 POSIX.1-2001 and POSIX.1-2001 TC2 required the functions |