Re: [PATCH] fix build failure with getline.c

[Eric Blake]

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According to Simon Josefsson on 1/1/2010 3:43 PM:
>> with an older glibc that didn't yet expose everything required by POSIX 2008?
> 
> Is there really a requirement for stdio.h to define ssize_t?  Glibc's
> stdio.h doesn't define ssize_t:

Yes, POSIX (but not C99) requires <stdio.h> to define ssize_t:

http://www.opengroup.org/onlinepubs/9699919799/basedefs/stdio.h.html#tag_13_49

Since it is listed with CX shading on that page, you must use either
define _GNU_SOURCE (to anything) or _POSIX_C_SOURCE (to 200809L) prior to
including <stdio.h> to see ssize_t.  And if glibc doesn't expose the type
even in those conditions, then that is a bug that gnulib needs to work around.

> It is possible to declare functions with ssize_t-parameters without
> using ssize_t directly, which is what glibc is doing.

Indeed, I see this with headers from glibc 2.7:

$ echo '#include <stdio.h>' | gcc -E - | grep ssize_t
typedef long int __ssize_t;
typedef __ssize_t __io_read_fn (void *__cookie, char *__buf, size_t __nbytes);
typedef __ssize_t __io_write_fn (void *__cookie, __const char *__buf,
extern __ssize_t _IO_padn (_IO_FILE *, int, __ssize_t);

$ echo '#include <stdio.h>' | gcc -D_GNU_SOURCE -E - | grep ssize_t
typedef long int __ssize_t;
typedef __ssize_t __io_read_fn (void *__cookie, char *__buf, size_t __nbytes);
typedef __ssize_t __io_write_fn (void *__cookie, __const char *__buf,
extern __ssize_t _IO_padn (_IO_FILE *, int, __ssize_t);
extern __ssize_t __getdelim (char **__restrict __lineptr,
extern __ssize_t getdelim (char **__restrict __lineptr,
extern __ssize_t getline (char **__restrict __lineptr,

I also checked the latest glibc.git, and couldn't see ssize_t or va_list
exposed, so I filed this bug report:

http://sources.redhat.com/bugzilla/show_bug.cgi?id=11125

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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