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Non-Compliant Code Example

The following non-compliant code example simply illustrates calling the standard string handling function strlen() with a plain character string, a signed character string, and an unsigned character string:

#include <string.h>

int main(void) {
  size_t len;
  char cstr[] = "char string";
  signed char scstr[] = "signed char string";
  unsigned char msgucstr[100];

Compliant Solution

] = "unsigned char string";

  len = strlen(cstr);
  len = strlen(scstr);  /* warns when char is unsigned */
  len = strlen(ucstr);  /* warns when char is signed */
  return 0;
}

Compiling at high warning levels, in compliance with MSC00-A. Compile cleanly at high warning levels causes warnings to be issue when converting from unsigned char[] to const char * when char is signed, and from signed char[] to const char * when char is defined to be unsigned. Casts are required to eliminate these warnings, but excessive casts can make code difficult to read and hide legitimate warning messages.

If this C code were to compiled using a C++ compiler, conversions between from unsigned char[] to const char * and from signed char[] to const char * would be be flagged as errors requiring casts.

Compliant Solution

The compliant solution uses plain char for character data.

#include <string.h>

int main(void) {
  size_t len;
  char error_msgcstr[100];] = "char string";

  len = strlen(cstr);
  return 0;
}

Risk Assessment

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