https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63499
Bug ID: 63499
Summary: gcc treats unknown -Wno-xxx options differently than
-Wxxx
Product: gcc
Version: 4.9.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: zbyszek at in dot waw.pl
$ echo 'int main(){}' > test.c
$ gcc -Wyyy test.c
gcc: error: unrecognized command line option ‘-Wyyy’
$ gcc -Wno-yyy test.c && echo OK
OK
$ gcc -Wall -Wno-yyy test.c && echo OK
test.c: In function ‘main’:
test.c:1:1: warning: control reaches end of non-void function [-Wreturn-type]
int main(){}
^
test.c: At top level:
cc1: warning: unrecognized command line option "-Wno-yyy"
OK
Depending on whether a different a different warning is emitted, the -Wno-*
options might cause a warning or not. "Positive" -W* options always emit an
error. This makes it hard to actually detect option support in a ./configure
script.
$ rpm -q gcc
gcc-4.9.1-11.fc21.x86_64
