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544ce845de
getopt can print a whole bunch of error messages, and when used standalone (from gnulib) it uses fprintf to do that. But fprintf is a cancellation point and getopt isn't, and also applying fprintf to a stream in wide-character mode is not allowed. glibc has an internal function called __fxprintf that writes a narrow format string to a stream regardless of mode, but it only handles ASCII format strings, and it's still a cancellation point. getopt's messages are translated, so they might not be ASCII. So getopt has an error message to an asprintf buffer, monkeys with internal flag bits on stderr to disable cancellation, and then calls __fxprintf(stderr, "%s", buffer). There isn't even a helper function, the code is duplicated every time. This patch fixes __fxprintf to handle arbitrary multibyte format strings, and adds a variant __fxprintf_nocancel that does the same thing but also isn't a cancellation point. (It still _works_ by monkeying with internal flag bits on the FILE, but that's not really a layering violation for code in stdio-common.) All of the #ifdef _LIBC blocks can then be reduced to their standalone versions with a little help from some macros at the top of the file. I also wrote a test case to verify that getopt really isn't a cancellation point, and I'm glad I did, because it found two bugs, one of which wasn't even to do with cancellation (see previous patch). * stdio-common/fxprintf.c (__fxprintf_nocancel): New function. (locked_vfxprintf): New helper function. Handle arbitrary multibyte strings, not just ASCII. * include/stdio.h: Declare __fxprintf_nocancel. * posix/getopt.c: When _LIBC is defined, define fprintf to __fxprintf_nocancel, flockfile to _IO_flockfile, and funlockfile to _IO_funlockfile. When neither _LIBC nor _POSIX_THREAD_SAFE_FUNCTIONS is defined, define flockfile and funlockfile as no-ops. (_getopt_internal_r): Remove all internal #ifdef _LIBC blocks; the standalone error-printing code can now be used for libc as well. Add an flockfile/funlockfile pair around one case where the error message is printed in several chunks. Don't use fputc. * posix/tst-getopt-cancel.c: New test. * posix/Makefile: Run it.
193 lines
7.2 KiB
C
193 lines
7.2 KiB
C
#ifndef _STDIO_H
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# if defined __need_FILE || defined __need___FILE || defined _ISOMAC
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# include <libio/stdio.h>
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# else
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# include <libio/stdio.h>
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/* Now define the internal interfaces. */
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__BEGIN_DECLS
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extern int __fcloseall (void);
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extern int __snprintf (char *__restrict __s, size_t __maxlen,
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const char *__restrict __format, ...)
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__attribute__ ((__format__ (__printf__, 3, 4)));
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libc_hidden_proto (__snprintf)
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extern int __vsnprintf (char *__restrict __s, size_t __maxlen,
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const char *__restrict __format, _G_va_list __arg)
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__attribute__ ((__format__ (__printf__, 3, 0)));
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extern int __vfscanf (FILE *__restrict __s,
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const char *__restrict __format,
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_G_va_list __arg)
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__attribute__ ((__format__ (__scanf__, 2, 0)));
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libc_hidden_proto (__vfscanf)
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extern int __vscanf (const char *__restrict __format,
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_G_va_list __arg)
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__attribute__ ((__format__ (__scanf__, 1, 0)));
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extern _IO_ssize_t __getline (char **__lineptr, size_t *__n,
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FILE *__stream);
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extern int __vsscanf (const char *__restrict __s,
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const char *__restrict __format,
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_G_va_list __arg)
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__attribute__ ((__format__ (__scanf__, 2, 0)));
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# ifndef __cplusplus
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extern int __sprintf_chk (char *, int, size_t, const char *, ...) __THROW;
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extern int __snprintf_chk (char *, size_t, int, size_t, const char *, ...)
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__THROW;
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extern int __vsprintf_chk (char *, int, size_t, const char *,
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_G_va_list) __THROW;
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extern int __vsnprintf_chk (char *, size_t, int, size_t, const char *,
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_G_va_list) __THROW;
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extern int __printf_chk (int, const char *, ...);
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extern int __fprintf_chk (FILE *, int, const char *, ...);
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extern int __vprintf_chk (int, const char *, _G_va_list);
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extern int __vfprintf_chk (FILE *, int, const char *, _G_va_list);
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extern char *__fgets_unlocked_chk (char *buf, size_t size, int n, FILE *fp);
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extern char *__fgets_chk (char *buf, size_t size, int n, FILE *fp);
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extern int __asprintf_chk (char **, int, const char *, ...) __THROW;
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extern int __vasprintf_chk (char **, int, const char *, _G_va_list) __THROW;
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extern int __dprintf_chk (int, int, const char *, ...);
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extern int __vdprintf_chk (int, int, const char *, _G_va_list);
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extern int __obstack_printf_chk (struct obstack *, int, const char *, ...)
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__THROW;
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extern int __obstack_vprintf_chk (struct obstack *, int, const char *,
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_G_va_list) __THROW;
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# endif
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extern int __isoc99_fscanf (FILE *__restrict __stream,
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const char *__restrict __format, ...) __wur;
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extern int __isoc99_scanf (const char *__restrict __format, ...) __wur;
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extern int __isoc99_sscanf (const char *__restrict __s,
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const char *__restrict __format, ...) __THROW;
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extern int __isoc99_vfscanf (FILE *__restrict __s,
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const char *__restrict __format,
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_G_va_list __arg) __wur;
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extern int __isoc99_vscanf (const char *__restrict __format,
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_G_va_list __arg) __wur;
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extern int __isoc99_vsscanf (const char *__restrict __s,
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const char *__restrict __format,
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_G_va_list __arg) __THROW;
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libc_hidden_proto (__isoc99_vsscanf)
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libc_hidden_proto (__isoc99_vfscanf)
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/* Prototypes for compatibility functions. */
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extern FILE *__new_tmpfile (void);
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extern FILE *__old_tmpfile (void);
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# define __need_size_t
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# define __need_wint_t
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# include <stddef.h>
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/* Generate a unique file name (and possibly open it). */
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extern int __path_search (char *__tmpl, size_t __tmpl_len,
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const char *__dir, const char *__pfx,
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int __try_tempdir);
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extern int __gen_tempname (char *__tmpl, int __suffixlen, int __flags,
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int __kind);
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/* The __kind argument to __gen_tempname may be one of: */
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# define __GT_FILE 0 /* create a file */
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# define __GT_DIR 1 /* create a directory */
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# define __GT_NOCREATE 2 /* just find a name not currently in use */
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/* Print out MESSAGE on the error output and abort. */
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extern void __libc_fatal (const char *__message)
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__attribute__ ((__noreturn__));
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extern void __libc_message (int do_abort, const char *__fnt, ...);
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extern void __fortify_fail (const char *msg)
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__attribute__ ((__noreturn__)) internal_function;
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libc_hidden_proto (__fortify_fail)
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/* Acquire ownership of STREAM. */
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extern void __flockfile (FILE *__stream);
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/* Relinquish the ownership granted for STREAM. */
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extern void __funlockfile (FILE *__stream);
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/* Try to acquire ownership of STREAM but do not block if it is not
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possible. */
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extern int __ftrylockfile (FILE *__stream);
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extern int __getc_unlocked (FILE *__fp);
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extern wint_t __getwc_unlocked (FILE *__fp);
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extern int __fxprintf (FILE *__fp, const char *__fmt, ...)
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__attribute__ ((__format__ (__printf__, 2, 3)));
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extern int __fxprintf_nocancel (FILE *__fp, const char *__fmt, ...)
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__attribute__ ((__format__ (__printf__, 2, 3)));
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extern const char *const _sys_errlist_internal[] attribute_hidden;
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extern int _sys_nerr_internal attribute_hidden;
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libc_hidden_proto (__asprintf)
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# if IS_IN (libc)
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extern _IO_FILE *_IO_new_fopen (const char*, const char*);
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# define fopen(fname, mode) _IO_new_fopen (fname, mode)
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extern _IO_FILE *_IO_new_fdopen (int, const char*);
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# define fdopen(fd, mode) _IO_new_fdopen (fd, mode)
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extern int _IO_new_fclose (_IO_FILE*);
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# define fclose(fp) _IO_new_fclose (fp)
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extern int _IO_fputs (const char*, _IO_FILE*);
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libc_hidden_proto (_IO_fputs)
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# define fputs(str, fp) _IO_fputs (str, fp)
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extern int _IO_new_fsetpos (_IO_FILE *, const _IO_fpos_t *);
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# define fsetpos(fp, posp) _IO_new_fsetpos (fp, posp)
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extern int _IO_new_fgetpos (_IO_FILE *, _IO_fpos_t *);
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# define fgetpos(fp, posp) _IO_new_fgetpos (fp, posp)
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# endif
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libc_hidden_proto (dprintf)
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extern __typeof (dprintf) __dprintf
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__attribute__ ((__format__ (__printf__, 2, 3)));
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libc_hidden_proto (__dprintf)
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libc_hidden_proto (fprintf)
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libc_hidden_proto (vfprintf)
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libc_hidden_proto (sprintf)
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libc_hidden_proto (sscanf)
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libc_hidden_proto (fwrite)
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libc_hidden_proto (perror)
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libc_hidden_proto (remove)
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libc_hidden_proto (rewind)
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libc_hidden_proto (fileno)
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extern __typeof (fileno) __fileno;
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libc_hidden_proto (__fileno)
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libc_hidden_proto (fwrite)
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libc_hidden_proto (fseek)
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extern __typeof (ftello) __ftello;
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libc_hidden_proto (__ftello)
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libc_hidden_proto (fflush)
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libc_hidden_proto (fflush_unlocked)
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extern __typeof (fflush_unlocked) __fflush_unlocked;
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libc_hidden_proto (__fflush_unlocked)
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extern __typeof (fread_unlocked) __fread_unlocked;
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libc_hidden_proto (__fread_unlocked)
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libc_hidden_proto (fwrite_unlocked)
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libc_hidden_proto (fgets_unlocked)
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extern __typeof (fgets_unlocked) __fgets_unlocked;
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libc_hidden_proto (__fgets_unlocked)
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libc_hidden_proto (fputs_unlocked)
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extern __typeof (fputs_unlocked) __fputs_unlocked;
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libc_hidden_proto (__fputs_unlocked)
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libc_hidden_proto (fmemopen)
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/* The prototype needs repeating instead of using __typeof to use
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__THROW in C++ tests. */
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extern FILE *__open_memstream (char **, size_t *) __THROW __wur;
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libc_hidden_proto (__open_memstream)
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libc_hidden_proto (__libc_fatal)
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rtld_hidden_proto (__libc_fatal)
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libc_hidden_proto (__vsprintf_chk)
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libc_hidden_proto (__vsnprintf_chk)
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libc_hidden_proto (__vfprintf_chk)
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libc_hidden_proto (__vasprintf_chk)
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libc_hidden_proto (__vdprintf_chk)
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libc_hidden_proto (__obstack_vprintf_chk)
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extern FILE * __fmemopen (void *buf, size_t len, const char *mode);
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libc_hidden_proto (__fmemopen)
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__END_DECLS
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# endif
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#endif
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