cert-err33-c

Warns on unused function return values. Many of the standard library functions return a value that indicates if the call was successful. Ignoring the returned value can cause unexpected behavior if an error has occurred. The following functions are checked:

• aligned_alloc()

• asctime_s()

• at_quick_exit()

• atexit()

• bsearch()

• bsearch_s()

• btowc()

• c16rtomb()

• c32rtomb()

• calloc()

• clock()

• cnd_broadcast()

• cnd_init()

• cnd_signal()

• cnd_timedwait()

• cnd_wait()

• ctime_s()

• fclose()

• fflush()

• fgetc()

• fgetpos()

• fgets()

• fgetwc()

• fopen()

• fopen_s()

• fprintf()

• fprintf_s()

• fputc()

• fputs()

• fputwc()

• fputws()

• fread()

• freopen()

• freopen_s()

• fscanf()

• fscanf_s()

• fseek()

• fsetpos()

• ftell()

• fwprintf()

• fwprintf_s()

• fwrite()

• fwscanf()

• fwscanf_s()

• getc()

• getchar()

• getenv()

• getenv_s()

• gets_s()

• getwc()

• getwchar()

• gmtime()

• gmtime_s()

• localtime()

• localtime_s()

• malloc()

• mbrtoc16()

• mbrtoc32()

• mbsrtowcs()

• mbsrtowcs_s()

• mbstowcs()

• mbstowcs_s()

• memchr()

• mktime()

• mtx_init()

• mtx_lock()

• mtx_timedlock()

• mtx_trylock()

• mtx_unlock()

• printf_s()

• putc()

• putwc()

• raise()

• realloc()

• remove()

• rename()

• setlocale()

• setvbuf()

• scanf()

• scanf_s()

• signal()

• snprintf()

• snprintf_s()

• sprintf()

• sprintf_s()

• sscanf()

• sscanf_s()

• strchr()

• strerror_s()

• strftime()

• strpbrk()

• strrchr()

• strstr()

• strtod()

• strtof()

• strtoimax()

• strtok()

• strtok_s()

• strtol()

• strtold()

• strtoll()

• strtoumax()

• strtoul()

• strtoull()

• strxfrm()

• swprintf()

• swprintf_s()

• swscanf()

• swscanf_s()

• thrd_create()

• thrd_detach()

• thrd_join()

• thrd_sleep()

• time()

• timespec_get()

• tmpfile()

• tmpfile_s()

• tmpnam()

• tmpnam_s()

• tss_create()

• tss_get()

• tss_set()

• ungetc()

• ungetwc()

• vfprintf()

• vfprintf_s()

• vfscanf()

• vfscanf_s()

• vfwprintf()

• vfwprintf_s()

• vfwscanf()

• vfwscanf_s()

• vprintf_s()

• vscanf()

• vscanf_s()

• vsnprintf()

• vsnprintf_s()

• vsprintf()

• vsprintf_s()

• vsscanf()

• vsscanf_s()

• vswprintf()

• vswprintf_s()

• vswscanf()

• vswscanf_s()

• vwprintf_s()

• vwscanf()

• vwscanf_s()

• wcrtomb()

• wcschr()

• wcsftime()

• wcspbrk()

• wcsrchr()

• wcsrtombs()

• wcsrtombs_s()

• wcsstr()

• wcstod()

• wcstof()

• wcstoimax()

• wcstok()

• wcstok_s()

• wcstol()

• wcstold()

• wcstoll()

• wcstombs()

• wcstombs_s()

• wcstoumax()

• wcstoul()

• wcstoull()

• wcsxfrm()

• wctob()

• wctrans()

• wctype()

• wmemchr()

• wprintf_s()

• wscanf()

• wscanf_s()

This check is an alias of check bugprone-unused-return-value with a fixed set of functions.

Suppressing issues by casting to void is enabled by default and can be disabled by setting AllowCastToVoid option to false.

The check corresponds to a part of CERT C Coding Standard rule ERR33-C. Detect and handle standard library errors. The list of checked functions is taken from the rule, with following exception:

• The check can not differentiate if a function is called with NULL argument. Therefore the following functions are not checked: mblen, mbrlen, mbrtowc, mbtowc, wctomb, wctomb_s