INT07-A. Only use signed or unsigned char type for numeric values

The three types char, signed char, and unsigned char are collectively called the character types. Compilers have the latitude to define char to have the same range, representation, and behavior as either signed char or unsigned char. Irrespective of the choice made, char is a separate type from the other two and is not compatible with either.

Only use signed char and unsigned char types for the storage and use of numeric values.

Non-Compliant Code Example

This non-compliant code example :

char i;

Compliant Solution

This problem is easily repaired by explicitly declaring the string variable as unsigned char.

unsigned char i;

Risk Assessment

This is a subtle error that results in a disturbingly broad range of potentially severe vulnerabilities.

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this rule on the CERT website.

References

[[ISO/IEC 9899-1999]] Section 6.2.5, "Types"
[[MISRA 04]] Rule 6.2, "signed and unsigned char type shall be used only for the storage and use of numeric values."