re-entrant


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re-entrant

(programming)
Used to describe code which can have multiple simultaneous, interleaved, or nested invocations which will not interfere with each other. This is important for parallel processing, recursive functions or subroutines, and interrupt handling.

It is usually easy to arrange for multiple invocations (e.g. calls to a subroutine) to share one copy of the code and any read-only data but, for the code to be re-entrant, each invocation must use its own copy of any modifiable data (or synchronised access to shared data). This is most often achieved using a stack and allocating local variables in a new stack frame for each invocation. Alternatively, the caller may pass in a pointer to a block of memory which that invocation can use (usually for outputting the result) or the code may allocate some memory on a heap, especially if the data must survive after the routine returns.

Re-entrant code is often found in system software, such as operating systems and teleprocessing monitors. It is also a crucial component of multithreaded programs where the term "thread-safe" is often used instead of "re-entrant".
References in periodicals archive ?
The predictions for stress fields were compared with birefringence measurements and showed reasonable quantitative agreement with experimental data although some discrepancy was found near the re-entrant corner, where the stress was overestimated.
Moreover, the results of simulations based on the optimised transport models seem to qualitatively follow the trends of the re-entrant jet formation at the trailing edge of the sheet.
For the re-entrant inlet, it started and ended at a Reynolds number of 2000 and 6700, respectively, near the inlet of the tube (3 diameters from the inlet), and 2100 and 8500 near the exit (192 diameters from the inlet).
The Physiotherapy Registration Board is less likely to be the initial contact point for a re-entrant as they have maintained their registration.
The re-entrant chamber without central projection and with sharp edges provides higher swirl number than all other chambers.
This sets up re-entrant areas around areas of diminished electrical activity, such as is seen in incisional tachycardias, where a circuit exists around the non-conducting scar (23-25).
That is unlikely, however, and numerous features point to a date in the late 8th or the course of the 9th century: the proportions of the new outermost ogival-shaped axial step (a Khmer, not a Dvaravati feature); the presence of pairs of flee-standing lions (which first appear in Cambodian art at Sambor C1, probably of the late 8th century); recovered stuccos, including heads of teeth-baring guardians, somewhat reminiscent of those in Cham temples of the late 8th century; and extensions at the corners that with their multiple re-entrant angles evoke the flavour of 8th-9th-century octagonal-based stupas at the site of U Thong, north of Nakhon Pathom.
To the application developer, the system service requests appear as re-entrant C functions callable from an application.
The bradycardic (heart rate slowing) effect of ATP, in particular its transient blockade of atrio-ventricular nodal conduction, has been shown in multiple published clinical studies to terminate re-entrant PSVT involving the atrio-ventricular node.
With the front door set into a re-entrant porch, space at entrance level is divided by a central kitchen that shifts the axis.
Re-entrant training that targets people who are currently unemployed or not in the labour force;