AutosarC++19_03-M18.0.4

The time handling functions of library <ctime> shall not be used

Required inputs: IR

String-to-numeric conversions can fail silently, returning zero or an invalid value without indicating an error. Functions like std::atoi, std::atof, and std::strtol provide no portable error reporting. Use safe functions like std::stoi (which throws exceptions) or std::from_chars (which provides error codes) to properly detect and handle conversion failures.

Bad code (unsafe conversion):

std::string str = "not_a_number";
int value = std::atoi(str.c_str());   // ERROR: returns 0 silently
double d = std::atof(str.c_str());    // ERROR: returns 0.0 without reporting error
// No way to distinguish between "0" and failed conversion

Good code (using std::stoi with exception):

std::string str = "42";
try {
    int value = std::stoi(str);       // OK: throws on invalid format
    double d = std::stod(str);        // OK: throws on failure
} catch (const std::invalid_argument& e) {
    std::cerr << "Conversion failed: " << e.what() << std::endl;
}

Good code (using std::from_chars):

std::string str = "123";
int value;
auto [ptr, ec] = std::from_chars(str.data(), str.data() + str.size(), value);
if (ec == std::errc() && ptr == str.data() + str.size()) {
    // OK: conversion successful
} else {
    // Handle error explicitly
}

Good code (using strtol)

char *end;
const char* str = "123";
errno = 0;
const long value = strtol(str, &end, 10);
if (errno == 0 && str != end) {
    printf("value: %ld\n", value); // OK: conversion successful
} else {
    printf("conversion failed\n");
}

Note

For legal reasons, this rule’s description is not part of the public documentation.