Cygwin: define FILE as struct __sFILE64, not as __sFILE

Until Cygwin 3.3.6, we define __LARGE64_FILES unconditionally, so we
were using the type __sFILE64 even for 64 bit.  That was lazy and wrong.
so commit 2902b3a09e ("Cygwin: drop requirement to build newlib's
stdio64") tried to fix that.

Unfortunately this patch forgot to take the exposure of the typename
__sFILE64 in userspace into account.  This leads to trouble in C++ due
to name mangling.

Commit 0f376ae220 tried to fix this by just renaming __sFILE to
__sFILE64 by using a macro.  While __sFILE and __sFILE64 are the same
size, they are not exactly congruent.

To avoid backward compatibility problems, make sure to define FILE
as the  real __sFILE64, and make sure that __sFILE is not defined at
all on Cygwin.

Fixes: 0f376ae220 ("Cygwin: rename __sFILE to __sFILE64 for backward
compatibility")
Fixes: 2902b3a09e ("Cygwin: drop requirement to build newlib's stdio64")
Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This commit is contained in:
Corinna Vinschen 2022-12-08 16:03:06 +01:00
parent 6429a7a7f6
commit 55de3fdd0e
2 changed files with 17 additions and 7 deletions

View File

@ -144,6 +144,11 @@ struct __sbuf {
#define _REENT_SMALL_CHECK_INIT(ptr) /* nothing */
/* Cygwin must use __sFILE64 for backward compatibility, even though
it's not defining __LARGE64_FILES anymore. To make sure that __sFILE
is never defined, disable it here explicitely. */
#ifndef __CYGWIN__
struct __sFILE {
unsigned char *_p; /* current position in (some) buffer */
int _r; /* read space left for getc() */
@ -195,13 +200,24 @@ struct __sFILE {
int _flags2; /* for future use */
};
#endif /* !__CYGWIN__ */
#ifdef __CUSTOM_FILE_IO__
/* Get custom _FILE definition. */
#include <sys/custom_file.h>
#else /* !__CUSTOM_FILE_IO__ */
#ifdef __LARGE64_FILES
/* Cygwin must use __sFILE64 for backward compatibility, even though
it's not defining __LARGE64_FILES anymore. It also has to make
sure the name is the same to satisfy C++ name mangling. Overloading
_fpos64_t just fixes a build problem. The _seek64 function is
actually never used without __LARGE64_FILES being defined. */
#if defined (__LARGE64_FILES) || defined (__CYGWIN__)
#ifdef __CYGWIN__
#define _fpos64_t _fpos_t
#endif
struct __sFILE64 {
unsigned char *_p; /* current position in (some) buffer */
int _r; /* read space left for getc() */

View File

@ -49,12 +49,6 @@ extern inline struct _reent *__getreent (void)
#define __FILENAME_MAX__ 4096 /* Keep in sync with PATH_MAX in limits.h. */
/* Unfortunately we defined __LARGE64_FILES until Cygwin 3.3.6, so
FILE was based on `struct __sFILE64'. The name is exposed into
userspace and consequentially used in C++ name mangling. We must
redefine __sFILE as __sFILE64 to stay backward compatible. */
#define __sFILE __sFILE64
/* The following block of macros is required to build newlib correctly for
Cygwin. Changing them in applications has no or not the desired effect.
Just leave them alone. */