According to MISRA 2008, concatenation of wide and narrow string literals leads to undefined behavior. This was once considered implicitly undefined behavior until C90 [ISO/IEC 9899:1990]. However, C99 defined this behavior [ISO/IEC 9899:1999], and C11 further explains in section 6.4.5, paragraph 5 [ISO/IEC 9899:2011]:
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Nonetheless, it is recommended that string literals that are concatenated should all be the same type so as not to rely on implementation-defined behavior or undefined behavior if compiled on a platform that supports only C90.
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This noncompliant code example concatenates wide and narrow string literals. Although the behavior is undefined in C90, the programmer probably intended to create a wide - string literal.
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wchar_t *msg = L"This message is very long, so I want to divide it "
"into two parts.";
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Search for vulnerabilities resulting from the violation of this rule on the CERT website.
Related Guidelines
| MISRA-C++ | Rule 2-13-5: MISRA.STRINGS.CONCAT Narrow and wide string literals concatenated |
Bibliography
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| 2011] | Section 6.4.5, "String |
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| Literals" |
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