SEI CERT C Coding Standard

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Code Block
bgColor#ccccff
langc
#include <limits.h>
#include <stddef.h>
#include <inttypes.h>

extern size_t popcount(uintmax_t);
#define PRECISION(x) popcount(x)
 
void func(unsigned int ui_a, unsigned int ui_b) {
  unsigned int uresult = 0;
  if (ui_b >= PRECISION(UINT_MAX)) {
    /* Handle error condition */
  } else {
    uresult = ui_a << ui_b;
  }

  /* ... */
}

The PRECISION() macro is defined in macro provides the correct precision for any integer type (see INT35-C. Use correct integer precisions). Modulo behavior resulting from left-shifting an unsigned integer type is permitted by exception INT30-EX3 to INT30-C. Ensure that unsigned integer operations do not wrap.

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