blob: 0f33abfb2e318d8a0cc75d8521844784ee17784d [file] [log] [blame]
.. title:: clang-tidy - bugprone-unused-return-value
Warns on unused function return values. The checked functions can be configured.
.. option:: CheckedFunctions
Semicolon-separated list of functions to check. The function is checked if
the name and scope matches, with any arguments.
By default the following functions are checked:
``std::async, std::launder, std::remove, std::remove_if, std::unique,
std::unique_ptr::release, std::basic_string::empty, std::vector::empty,
std::back_inserter, std::distance, std::find, std::find_if, std::inserter,
std::lower_bound, std::make_pair, std::map::count, std::map::find,
std::map::lower_bound, std::multimap::equal_range,
std::multimap::upper_bound, std::set::count, std::set::find, std::setfill,
std::setprecision, std::setw, std::upper_bound, std::vector::at,
bsearch, ferror, feof, isalnum, isalpha, isblank, iscntrl, isdigit, isgraph,
islower, isprint, ispunct, isspace, isupper, iswalnum, iswprint, iswspace,
isxdigit, memchr, memcmp, strcmp, strcoll, strncmp, strpbrk, strrchr,
strspn, strstr, wcscmp, access, bind, connect, difftime, dlsym, fnmatch,
getaddrinfo, getopt, htonl, htons, iconv_open, inet_addr, isascii, isatty,
mmap, newlocale, openat, pathconf, pthread_equal, pthread_getspecific,
pthread_mutex_trylock, readdir, readlink, recvmsg, regexec, scandir,
semget, setjmp, shm_open, shmget, sigismember, strcasecmp, strsignal,
- ``std::async()``. Not using the return value makes the call synchronous.
- ``std::launder()``. Not using the return value usually means that the
function interface was misunderstood by the programmer. Only the returned
pointer is "laundered", not the argument.
- ``std::remove()``, ``std::remove_if()`` and ``std::unique()``. The returned
iterator indicates the boundary between elements to keep and elements to be
removed. Not using the return value means that the information about which
elements to remove is lost.
- ``std::unique_ptr::release()``. Not using the return value can lead to
resource leaks if the same pointer isn't stored anywhere else. Often,
ignoring the ``release()`` return value indicates that the programmer
confused the function with ``reset()``.
- ``std::basic_string::empty()`` and ``std::vector::empty()``. Not using the
return value often indicates that the programmer confused the function with
`cert-err33-c <cert-err33-c.html>`_ is an alias of this check that checks a
fixed and large set of standard library functions.