CERT® C Coding Standard, Second Edition, The; .

Ensure that operations on signed integers do not result in overflow 126 INT33-C. Ensure that division and remainder operations do not result in divide-by-zero errors 135 INT34-C. Do not shift an expression by a negative number of bits or by greater than or equal to the number of bits that exist in the operand 138 INT35-C. Use correct integer precisions 143 INT36-C. Converting a pointer to integer or integer to pointer 145 Chapter 5: Floating Point (FLP) 151 FLP30-C. Do not use floating-point variables as loop counters 152 FLP32-C. Prevent or detect domain and range errors in math functions 154 FLP34-C. Ensure that floating-point conversions are within range of the new type 163 FLP36-C. Preserve precision when converting integral values to floating-point type 166 Chapter 6: Arrays (ARR) 169 ARR30-C. Do not form or use out-of-bounds pointers or array subscripts 170 ARR32-C. Ensure size arguments for variable length arrays are in a valid range 180 ARR36-C. Do not subtract or compare two pointers that do not refer to the same array 182 ARR37-C. Do not add or subtract an integer to a pointer to a non-array object 184 ARR38-C. Guarantee that library functions do not form invalid pointers 187 ARR39-C. Do not add or subtract a scaled integer to a pointer 196 Chapter 7: Characters and Strings (STR) 201 STR30-C. Do not attempt to modify string literals 202 STR31-C. Guarantee that storage for strings has sufficient space for character data and the null terminator 205 STR32-C. Do not pass a non-null-terminated character sequence to a library function that expects a string 218 STR34-C. Cast characters to unsigned char before converting to larger integer sizes 223 STR37-C. Arguments to character handling functions must be representable as an unsigned char 227 STR38-C. Do not confuse narrow and wide character strings and functions 229 Chapter 8: Memory Management (MEM) 233 MEM30-C. Do not access freed memory 234 MEM31-C. Free dynamically allocated memory when no longer needed 239 MEM33-C. Allocate and copy structures containing a flexible array member dynamically 241 MEM34-C. Only free memory allocated dynamically 246 MEM35-C. Allocate sufficient memory for an object 250 MEM36-C. Do not modify the alignment of objects by calling realloc() 253 Chapter 9: Input/Output (FIO) 257 FIO30-C. Exclude user input from format strings 258 FIO31-C. Do not open a file that is already open 263 FIO32-C. Do not perform operations on devices that are only appropriate for files 265 FIO34-C. Distinguish between characters read from a file and EOF or WEOF 272 FIO37-C. Do not assume that fgets() or fgetws() returns a nonempty string when successful 277 FIO38-C. Do not copy a FILE object 279 FIO39-C. Do not alternately input and output from a stream without an intervening flush or positioning call 280 FIO40-C. Reset strings on fgets() or fgetws() failure 283 FIO41-C. Do not call getc(), putc(), getwc(), or putwc() with a stream argument that has side effects 284 FIO42-C. Close files when they are no longer needed 288 FIO44-C. Only use values for fsetpos() that are returned from fgetpos() 292 FIO45-C. Avoid TOCTOU race conditions while accessing files 294 FIO46-C. Do not access a closed file 298 FIO47-C. Use valid format strings 299 Chapter 10: Environment (ENV) 305 ENV30-C. Do not modify the object referenced by the return value of certain functions 306 ENV31-C. Do not rely on an environment pointer following an operation that may invalidate it 311 ENV32-C. All exit handlers must return normally 315 ENV33-C. Do not call system() 319 ENV34-C. Do not store pointers returned by certain functions 325 Chapter 11: Signals (SIG) 333 SIG30-C. Call only asynchronous-safe functions within signal handlers 334 SIG31-C. Do not access shared objects in signal handlers 342 SIG34-C. Do not call signal() from within interruptible signal handlers 345 SIG35-C. Do not return from a computational exception signal handler 349 Chapter 12: Error Handling (ERR) 353 ERR30-C. Set errno to zero before calling a library function known to set errno, and check errno only after the function returns a value indicating failure 354 ERR32-C. Do not rely on indeterminate values of errno 361 ERR33-C. Detect and handle standard library errors 365 Chapter 13: Concurrency (CON) 383 CON30-C. Clean up thread-specific storage 384 CON31-C. Do not destroy a mutex while it is locked 388 CON32-C. Prevent data races when accessing bit-fields from multiple threads 391 CON33-C. Avoid race conditions when using library functions 394 CON34-C. Declare objects shared between threads with appropriate storage durations 398 CON35-C. Avoid deadlock by locking in a predefined order 406 CON36-C. Wrap functions that can spuriously wake up in a loop 411 CON37-C. Do not call signal() in a multithreaded program 414 CON38-C. Preserve thread-safety and liveness when using condition variables 416 CON39-C. Do not join or detach a thread that was previously joined or detached 424 CON40-C. Do not refer to an atomic variable twice in an expression 426 CON41-C. Wrap functions that can fail spuriously in a loop 430 Chapter 14: Miscellaneous (MSC) 435 MSC30-C. Do not use the rand() function for generating pseudorandom numbers 436 MSC32-C. Properly seed pseudorandom number generators 439 MSC33-C. Do not pass invalid data to the asctime() function 443 MSC37-C. Ensure that control never reaches the end of a non-void function 446 MSC38-C. Do not treat a predefined identifier as an object if it might only be implemented as a macro 449 MSC39-C. Do not call va_arg() on a va_list that has an indeterminate value 451 MSC40-C. Do not violate constraints 453 Appendix A: Glossary 459 Appendix B: Undefined Behavior 465 Appendix C: Unspecified Behavior 481 Bibliography 487 Index 495