Re: /usr/include/ssp/wchar.h:78:1: error: unknown type name ‘FILE’ (during cygport package build)

[Hans-Bernhard Bröker <HBBroeker at t-online dot de>]

Am 13.05.2018 um 18:01 schrieb waterlan:

> The C flag that triggers this option is -Wp,-D_FORTIFY_SOURCE=2.

That does look rather weird.  Why would one write that instead of just 
-D_FORTIFY_SOURCE=2 ?

Anyway, the test can be simplified quite a lot to:

hbbro@NB4 ~/tmp
$ cat twchar.c
#include <wchar.h>



$ gcc -D_FORTIFY_SOURCE=1 -fstack-protector-strong -c twchar.c -O2 
-D_XOPEN_SOURCE
In file included from /usr/include/ssp/wchar.h:5:0,
                 from /usr/include/wchar.h:336,
                 from twchar.c:1:
/usr/include/ssp/wchar.h:78:1: error: unknown type name 'FILE'
 __ssp_decl(wchar_t *, fgetws, (wchar_t *__restrict __buf, int __wlen, 
FILE *__restrict __fp))
 ^
/usr/include/ssp/wchar.h:78:1: error: unknown type name 'FILE'
 __ssp_decl(wchar_t *, fgetws, (wchar_t *__restrict __buf, int __wlen, 
FILE *__restrict __fp))


All four of the GCC options have to be there to trigger this 
(_FORTIFY_SOURCE can be set to 2, for the same result).  Basically the 
SSP additions to <wchar.h> fail to compile, but only if the feature set 
has been restricted from the default by -D_XOPEN_SOURCE.  Ultimately 
this happens because the latter disables the typedef of FILE in 
/usr/include/wchar.h line 72 ff:

#if __POSIX_VISIBLE >= 200809 || _XSI_VISIBLE
/* As in stdio.h, <sys/reent.h> defines __FILE. */
#if !defined(__FILE_defined)
typedef __FILE FILE;
# define __FILE_defined
#endif
#endif

I don't know remotely enough about this SSP stuff to judge if that's 
even supposed to work in -D_XOPEN_SOURCE mode.  But as it is, it can't.

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