This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
The functionality described on this reference page is aligned with
the ISO C standard. Any conflict between the requirements described
here and the ISO C standard is unintentional. This volume of
POSIX.1‐2008 defers to the ISO C standard.
The abort() function shall cause abnormal process termination to
occur, unless the signal SIGABRT is being caught and the signal
handler does not return.
The abnormal termination processing shall include the default actions
defined for SIGABRT and may include an attempt to effect fclose() on
all open streams.
The SIGABRT signal shall be sent to the calling process as if by
means of raise() with the argument SIGABRT.
The status made available to wait(), waitid(), or waitpid() by
abort() shall be that of a process terminated by the SIGABRT signal.
The abort() function shall override blocking or ignoring the SIGABRT
The ISO/IEC 9899:1999 standard requires the abort() function to be
async-signal-safe. Since POSIX.1‐2008 defers to the ISO C standard,
this required a change to the DESCRIPTION from ``shall include the
effect of fclose()'' to ``may include an attempt to effect
The revised wording permits some backwards-compatibility and avoids a
potential deadlock situation.
The Open Group Base Resolution bwg2002‐003 is applied, removing the
following XSI shaded paragraph from the DESCRIPTION:
``On XSI-conformant systems, in addition the abnormal termination
processing shall include the effect of fclose() on message catalog
There were several reasons to remove this paragraph:
* No special processing of open message catalogs needs to be
performed prior to abnormal process termination.
* The main reason to specifically mention that abort() includes the
effect of fclose() on open streams is to flush output queued on
the stream. Message catalogs in this context are read-only and,
therefore, do not need to be flushed.
* The effect of fclose() on a message catalog descriptor is
unspecified. Message catalog descriptors are allowed, but not
required to be implemented using a file descriptor, but there is
no mention in POSIX.1‐2008 of a message catalog descriptor using
a standard I/O stream FILE object as would be expected by
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) In the event of any discrepancy between this version and
the original IEEE and The Open Group Standard, the original IEEE and
The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
IEEE/The Open Group 2013 ABORT(3P)