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| CERT C Secure Coding Standard | STR37-C. Arguments to character-handling functions must be representable as an unsigned char STR04-C. Use plain char for characters in the basic character set ARR30-C. Do not form or use out-of-bounds pointers or array subscripts |
| SEI CERT C++ Coding Standard | VOID STR34-CPP. Cast characters to unsigned types before converting to larger integer sizes |
| ISO/IEC TS 17961:2013 | Conversion of signed characters to wider integer types before a check for EOF [signconv] |
| MISRA-C | Rule 10.1 through Rule 10.4 (required) |
| MITRE CWE | CWE-704, Incorrect Type Conversion or Cast |
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