Avoid in-band error indicators while designing interfaces. This practice is commonly used by C library functions but is not recommended. One example from the C standard of a troublesome in-band error indicator is EOF. (See rules FIO34-C. Use int to capture the return value of character IO functions and FIO35-C. Use feof() and ferror() to detect end-of-file and file errors when sizeof(int) == sizeof(char).) Another problematic use of in-band error indicators from the C standard involving the size_t and time_t types is described by rule MSC31-C. Ensure that return values are compared against the proper type.
Noncompliant Code Example (sprintf())
This specific noncompliant code example is from the Linux Kernel Mailing List archive site, although similar examples are common.
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