[Pw_forum] Error:forrtl: severe (174): SIGSEGV, segmentation fault occurred

Paolo Giannozzi giannozz at nest.sns.it
Thu Mar 17 15:35:36 CET 2005

On Thursday 17 March 2005 18:42, Nitya Nath wrote:

> forrtl: severe (174): SIGSEGV, segmentation fault occurred [...[
> Could you please tell me possibility of error?

there are many messages in the mailing list about this type of
error (please use the search facility). There is also some info in 
the manual. Segmentation fault means nothing more than
"something very wrong happened": the code is trying to access 
unaccessible memory or to write unwritable memory, typically. 
Even in the absence of any bug in the code, it can be produced by
- insufficient RAM memory
- insufficient stack size (especially with some compilers: try 
"ulimit -s unlimited" or "limits stacksize unlimited") 
- buggy compiler or optimization
- bad compilation options
- wrong or buggy libraries (system, mathematical, MPI)
It is very hard to locate the reason of a segmentation fault just
knowing that there is one.


Paolo Giannozzi             e-mail:  giannozz at nest.sns.it
Scuola Normale Superiore    Phone:   +39/050-509876, Fax:-563513 
Piazza dei Cavalieri 7      I-56126 Pisa, Italy

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