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.
#include <stdlib.h> void abort(void);
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.1-2017 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 signal.
The abort() function shall not return.
No errors are defined.
The following sections are informative.
Catching the signal is intended to provide the application developer with a portable means to abort processing, free from possible interference from any implementation-supplied functions.
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 fclose().”
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 descriptors.”
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 fclose().
exit(), kill(), raise(), signal(), wait(), waitid()
The Base Definitions volume of POSIX.1-2017, <stdlib.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. 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.opengroup.org/unix/online.html .
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