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In this non-compliant code example, an integer overflow is specifically checked looked for by checking whether length + 1 == 0 (that is, integer wrap around has occurred). If the test passes, a wrapper to malloc() is called to allocate the appropriate data block. In a program compiled using an ILP32 compiler, this code runs as expected, but in an LP64 environment, an integer overflow can occur because length is now a 64-bit value. The result of the expression, however, is truncated to 32 bits when passed as an argument to alloc() because it takes an unsigned int argument.
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