Re: [geomview-users] SaVi segfaulting when writing to a geomview pipe?

[Adrian R. <ad...@an...>]

Hi Lloyd

On Sat, 15 Jun 2019, llo...@ya... wrote:
> #    DEBUGFLAGS = -Wall -Wextra -Wconversion -pedantic -ansi
>
> The -ansi flag caused SaVi to segfault on writing to the geomview pipe 
> with recent gcc, removing that flag fixed it. But why? gcc 7.3 or later

If you look at the build warnings you will see

gv_utils.c: In function ‘gv_stream_init_proc’:
gv_utils.c:93:11: warning: implicit declaration of function ‘fileno’; did 
you mean ‘fopen’? [-Wimplicit-function-declaration]
    fdout = fileno(stdout);
            ^~~~~~
            fopen

It appears that the solution is to define _POSIX_C_SOURCE, e.g.

    make CC="gcc  -Wall -Wextra -Wconversion -pedantic -ansi -D_POSIX_C_SOURCE" ARCH=ubuntu

The resulting binary then runs correctly.

See here for some explanation

    https://stackoverflow.com/questions/25759672/ansi-c-and-temporary-files

Adrian.
-- 
Adrian Rossiter
ad...@an...
http://antiprism.com/adrian