On Thu, 2021-04-29 at 22:09 -0500, Peng Yu via Gcc-help wrote: > $ gcc -E - <<< '#include <stdio.h>' | head -n 1 > # 1 "<stdin>" > $ declare -p PIPESTATUS > declare -a PIPESTATUS=([0]="2" [1]="0") > $ gcc --version > gcc (Debian 10.2.1-6) 10.2.1 20210110 > Copyright (C) 2020 Free Software Foundation, Inc. > This is free software; see the source for copying conditions. There is > NO > warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR > PURPOSE. > > gcc returns 2 in the above example. This does not follow the standard > convention on Linux. > > For example, the exit status of seq is 141 which corresponds to a > SIGPIPE signal. > > $ seq 1000000 | head -n 1 > 1 > $ declare -p PIPESTATUS > declare -a PIPESTATUS=([0]="141" [1]="0") > > Should gcc conform to this standard as well? Thanks. > I don't think 141 is a "standard". And I can't find it in POSIX or LSB. POSIX 2017 Volumn "Shell & Utilities" section 1.4: > In some cases, status values are listed more loosely, such as >0. A > strictly conforming application shall not rely on any specific value in > the range shown and shall be prepared to receive any value in the range. And section 4 specified a C compiler named c99, where the exit status is said to be: > EXIT STATUS > > The following exit values shall be returned: > > 0 > Successful compilation or link edit. > >0 > An error occurred. So POSIX specifies that a C compiler can return anything > 0 for an error occurred. If you see an authoritive standard document saying "a C compiler should return 141 when pipe is broken", then report to https://gcc.gnu.org/bugzilla and put the URL of the standard document in the report. -- Xi Ruoyao <xry111@xxxxxxxxxxxxxxxx> School of Aerospace Science and Technology, Xidian University
