Why Does Valgrind Report \'Conditional Jump or Move Depends on Uninitialized Value(s)\' and How Can I Track the Origin?

Understanding and Resolving "Conditional Jump or Move Depends on Uninitialized Value(s)" Valgrind Message

Valgrind, a debugging tool for detecting memory errors, often reports "Conditional Jump or Move Depends on Uninitialized Value(s)" messages. This message indicates that a value has not been initialized before being used in a conditional jump or move operation.

Tracking the Origin of Uninitialized Values

However, valgrind sometimes only displays the location where the uninitialized value is used, not its origin. To address this, use the option --track-origins=yes. While it slows down valgrind's processing, it provides additional information about the value's origin.

Reporting Time ofUninitialized Value Usage

The valgrind manual explains that reporting may not occur immediately upon using an uninitialized value. Instead, it occurs when the program attempts to utilize the value in a way that could affect its visible behavior.

According to the Valgrind FAQ, eager reporting of uninitialized values is not currently supported due to the high rate of false positives caused by legitimate copying of uninitialized values.

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