abort - cause abnormal process termination
The abort() function first unblocks the SIGABRT signal, and then raises that signal for the calling process (as though raise(3) was called). This results in the abnormal termination of the process unless the SIGABRT signal is caught and the signal handler does not return (see longjmp(3)).
If the SIGABRT signal is ignored, or caught by a handler that returns, the abort() function will still terminate the process. It does this by restoring the default disposition for SIGABRT and then raising the signal for a second time.
The abort() function never returns.
For an explanation of the terms used in this section, see attributes(7).
Up until glibc 2.26, if the abort() function caused process termination, all open streams were closed and flushed (as with fclose(3)). However, in some cases this could result in deadlocks and data corruption. Therefore, starting with glibc 2.27, abort() terminates the process without flushing streams. POSIX.1 permits either possible behavior, saying that abort() "may include an attempt to effect fclose() on all open streams".
SVr4, POSIX.1-2001, POSIX.1-2008, 4.3BSD, C89, C99.