Message 309503 - Python tracker (original) (raw)

gcc is a little bit lost and prints now the following (false) warning:

gcc -pthread -Wno-unused-result -Wsign-compare -g -Og -Wall -Wstrict-prototypes -std=c99 -Wextra -Wno-unused-result -Wno-unused-parameter -Wno-missing-field-initializers -Werror=implicit-function-declaration -I. -I./Include -DPy_BUILD_CORE -c ./Modules/posixmodule.c -o Modules/posixmodule.o./Modules/posixmodule.c: In function ‘os_dup2_impl’: ./Modules/posixmodule.c:7785:9: warning: ‘res’ may be used uninitialized in this function [-Wmaybe-uninitialized] int res; ^~~

The following change fools gcc that does not print anymore the warning:

diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c index 47b79fcc79..90d73daf97 100644 --- a/Modules/posixmodule.c +++ b/Modules/posixmodule.c @@ -7845,7 +7845,7 @@ os_dup2_impl(PyObject *module, int fd, int fd2, int inheritable) } }

• if (inheritable || dup3_works == 0)

• if (inheritable || (!inheritable && dup3_works == 0)) {

#endif Py_BEGIN_ALLOW_THREADS

The change does not modify the behavior:

• dup3_works == 0 is equivalent to ((inheritable && dup3_works == 0) || (!inheritable && dup3_works == 0))
• (inheritable && dup3_works == 0) is always false
• hence dup3_works == 0 is equivalent to (!inheritable && dup3_works == 0)