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Uninitialized memory

As explained in Modern C

An uninitialized object is a C object whose stored value has not been given a valid initial value before it is read or otherwise used.

An uninitialized object has not been given a valid initial value. In C, using one can cause incorrect results, crashes, data loss, or exposure of sensitive information. section 15.0

Reduce the risk by initializing objects before use:

  • Initialize every block-scope variable. section 15.0
  • Use calloc instead of malloc when suitable, and provide an initialization function for more complicated dynamically allocated structures. section 15.0

How Modern C covers it

How deep it goes
Lists initialization measures for block-scope variables and dynamically allocated structures.
Examples
Uses block-scope variables and dynamically allocated structures as cases requiring initialization.
What you can do after
Apply initialization to block-scope variables and choose suitable initialization methods for dynamically allocated objects.
How it connects
Links uninitialized-object risks with out-of-bounds access, ended object lifetimes, and integer overflow.
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Related concepts

This explainer was generated by Manning's knowledge graph from the text of Modern C. The section links point to the parts of the book it draws on.