Gnat and non thread-safe C libraries

Gnat and non thread-safe C libraries

[Laurent Deniel]

 Hi all

 I am trying to migrate an Ada program to the Linux/gnat environment.
 The program makes use of the X library and of other non thread-safe
 C libraries. As gnat may internally use threads even if this program 
 does not contain Ada tasks, I encounter some random weird behaviors
 depending on the thread library:

 With the default one (FSU), the signal handling in one library is
 broken since some signals (SIGIO, SIGURG) are received (and the 
 associated handlers are executed) in some runtime thread context 
 while the user thread has blocked that signals (the library expects 
 that such signals are blocked at process level). I tried to use the
 Block_Interrupt procedure but without success (segmentation violation).

 With the native one (Linux kernel Threads), the signal handling is 
 compatible with all libraries but the errno value is incorrect in
 those that were not compiled with the flag _REENTRANT (like X lib).
 So a little question: is it possible to avoid thread usage in the 
 gnat runtime when a program does not make use of the Ada tasking ?

 Any other advises would be greatly appreciated ...

 Laurent.

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Laurent DENIEL            | E-mail: deniel@worldnet.fr
Paris, FRANCE             |         deniel@fr.airsysatm.thomson-csf.com
                          | WWW   : http://www.worldnet.fr/~deniel
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