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How do you know if a code is reentrant?

How do you know if a code is reentrant?

1 Answer. The way to determine if a function is reentrant is to analyse what it does. 2) The code is not self-modifying (fortunately, self-modifying code is relatively rare in standard C or C++).

What is reentrant function example?

Example of Reentrant Functions: If an interrupt that pauses its execution and shifts the control to fun1. After fun1 completes, the control is again transferred to fun2 and it reenters the execution phase.

How do you make a reentrant code?

To be reentrant, a computer program or routine:

  1. Must hold no static (or global) non-constant data.
  2. Must not return the address to static (or global) non-constant data.
  3. Must work only on the data provided to it by the caller.
  4. Must not rely on locks to singleton resources.
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What means reentrant?

reentering or pointing inward: a reentrant angle. noun. a reentering angle or part. a person or thing that reenters or returns: Reentrants to the engineering program must take the introductory course again.

What is the difference between reentrant and non-reentrant functions?

A reentrant function does not hold static data over successive calls, nor does it return a pointer to static data. A reentrant function must not call non-reentrant functions. A non-reentrant function can often, but not always, be identified by its external interface and its usage.

Are malloc and free thread-safe?

Yes, currently malloc() is thread-safe.

What is reentrant structure?

Unlike typical porous graphene structures, the reentrant structure provided structure-assisted stretchability, such as accordion and origami structures, to otherwise unstretchable materials. For practical applications, we fabricated all-solid-state supercapacitors based on 2D auxetic structures.

What is reentrant kernel?

A re-entrant kernel enables processes (or, to be more precise, their corresponding kernel threads) to give away the CPU while in kernel mode. They do not hinder other processes from also entering kernel mode. A typical use case is IO wait. The process wants to read a file.

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Which is not a reentrant function?

A function can be non-reentrant if it uses memory that is not on the stack. If a function uses a static variable or a global variable, or a dynamically-allocated object that it finds for itself, then it is non-reentrant and any two calls to the function can interfere.

Is malloc thread-safe on Windows?

Provided you’re linking with thread-safe libraries and using the correct flags, yes, malloc should be thread-safe.

Does malloc use mutex?

Doug Lea’s malloc used coarse locking (or no locking, depending on the configuration settings), where every call to malloc / realloc / free is protected by a global mutex.

What is a reentrant in geography?

A reentrant appears on the map as a U or V shape in the contour lines, pointing back into a hillside rather than sticking out of the hill (as would a spur). So a reentrant is a small valley, the center of which would collect water and funnel it downhill (if it were raining hard).

What is an example of a reentrant function?

Example of Reentrant Functions: In the below code, fun2 is a reentrant function. If an interrupt that pauses its execution and shifts the control to fun1. After fun1 completes, the control is again transferred to fun2 and it reenters the execution phase.

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What is a reentrant computer program?

A computer program or routine is described as reentrant if it can be safely called again before its previous invocation has been completed (i.e it can be safely executed concurrently). To be reentrant, a computer program or routine:

What are the requirements of a reentrant?

To be reentrant, a computer program or routine: Must hold no static (or global) non-constant data. Must not return the address to static (or global) non-constant data. Must work only on the data provided to it by the caller. Must not rely on locks to singleton resources.

What is re-entrant coding and how does it work?

Conceptually, re-entrant coding is as if several people were each baking a cake from a single copy of a recipe on the wall. Everyone follows the master recipe but keeps track of their individual progress by jotting down the step they are working on so they can pick up where they left off.