Integer literal assigned to an unsigned variable without a U suffix
ID |
c.maintainability.unsigned_literal_suffix |
Severity |
low |
Remediation Complexity |
trivial |
Remediation Risk |
low |
Remediation Effort |
low |
Resource |
Numeric Literal |
Language |
C / C++ |
Description
This integer literal is stored into an unsigned variable but has no U suffix, so the literal itself is signed and the compiler has to convert it. That mismatch between the literal’s own type and the variable’s type can silently change behavior once the literal grows past INT_MAX or is used in mixed signed/unsigned arithmetic. Add a U suffix, e.g. 5u, so the literal’s type already matches the variable it initializes.
Rationale
This integer literal is stored into an unsigned variable but has no U suffix, so the literal itself is signed and the compiler has to convert it. That mismatch between the literal’s own type and the variable’s type can silently change behavior once the literal grows past INT_MAX or is used in mixed signed/unsigned arithmetic. Add a U suffix, e.g. 5u, so the literal’s type already matches the variable it initializes.
The following code illustrates the pattern detected by this rule:
void configure(void)
{
// FLAGGED: Integer literal assigned to an unsigned variable without a U suffix
unsigned int retries = 5;
unsigned int b;
// FLAGGED: Integer literal assigned to an unsigned variable without a U suffix
b = 5;
unsigned int suffixed = 5u;
unsigned int upper = 5U;
unsigned int zero = 0;
unsigned long timeout;
// FLAGGED: Integer literal assigned to an unsigned variable without a U suffix
timeout = 1000;
unsigned long timeoutOk = 1000UL;
int signedCount = 5;
(void)retries;
(void)signedCount;
}