# Vault 7: Projects

This publication series is about specific projects related to the Vault 7 main publication.

### Protego

# MPLAB XC16 C-Compiler

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Diagnostics
 2012-2013 Microchip Technology Inc. DS50002071C-page 267
comparison between signed and unsigned
One of the operands of a comparison is signed, while the other is unsigned. The signed
operand will be treated as an unsigned value, which may not be correct.
comparison is always n
A comparison involves only constant expressions, so the compiler can evaluate the run
time result of the comparison. The result is always n.
comparison is always n due to width of bit-field
A comparison involving a bit-field always evaluates to n because of the width of the
bit-field.
comparison is always false due to limited range of data type
A comparison will always evaluate to false at run time, due to the range of the data
types.
comparison is always true due to limited range of data type
A comparison will always evaluate to true at run time, due to the range of the data
types.
comparison of promoted ~unsigned with constant
One of the operands of a comparison is a promoted ~unsigned, while the other is a
constant.
comparison of promoted ~unsigned with unsigned
One of the operands of a comparison is a promoted ~unsigned, while the other is
unsigned.
comparison of unsigned expression >= 0 is always true
A comparison expression compares an unsigned value with zero. Since unsigned
values cannot be less than zero, the comparison will always evaluate to true at run
time.
comparison of unsigned expression < 0 is always false
A comparison expression compares an unsigned value with zero. Since unsigned
values cannot be less than zero, the comparison will always evaluate to false at run
time.
comparisons like X<=Y<=Z do not have their mathematical meaning
A C expression does not necessarily mean the same thing as the corresponding
mathematical expression. In particular, the C expression X<=Y<=Z is not equivalent to
the mathematical expression X  Y  Z.
conflicting types for built-in function identifier
The specified function has the same name as a built-in function but is declared with
conflicting types.
const declaration for identifier follows non-const
The specified identifier was declared const after it was previously declared as
non-const.
control reaches end of non-void function
All exit paths from non-void function should return an appropriate value. The compiler
detected a case where a non-void function terminates, without an explicit return value.
Therefore, the return value might be unpredictable.
conversion lacks type at end of format
When checking the argument list of a call to printf, scanf, etc., the compiler found that
a format field in the format string lacked a type specifier.

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