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* Refer to C23 in place of C2X in glibcJoseph Myers2024-02-011-8/+8
| | | | | | | | | | | | | | | WG14 decided to use the name C23 as the informal name of the next revision of the C standard (notwithstanding the publication date in 2024). Update references to C2X in glibc to use the C23 name. This is intended to update everything *except* where it involves renaming files (the changes involving renaming tests are intended to be done separately). In the case of the _ISOC2X_SOURCE feature test macro - the only user-visible interface involved - support for that macro is kept for backwards compatibility, while adding _ISOC23_SOURCE. Tested for x86_64.
* C2x scanf %wN, %wfN supportJoseph Myers2023-09-281-0/+14
| | | | | | | | | ISO C2x defines scanf length modifiers wN (for intN_t / int_leastN_t / uintN_t / uint_leastN_t) and wfN (for int_fastN_t / uint_fastN_t). Add support for those length modifiers, similar to the printf support previously added. Tested for x86_64 and x86.
* C2x scanf %b supportJoseph Myers2023-06-191-3/+9
| | | | | | | | | | | | ISO C2x defines scanf %b for input of binary integers (with an optional 0b or 0B prefix). Implement such support, along with the corresponding SCNb* macros in <inttypes.h>. Unlike the support for binary integers with 0b or 0B prefix with scanf %i, this is supported in all versions of scanf (independent of the standards mode used for compilation), because there are no backwards compatibility concerns (%b wasn't previously a supported format) the way there were for %i. Tested for x86_64 and x86.
* C2x printf %wN, %wfN support (bug 24466)Joseph Myers2023-06-191-0/+18
| | | | | | | | | | | | | | | | | | ISO C2x defines printf length modifiers wN (for intN_t / int_leastN_t / uintN_t / uint_leastN_t) and wfN (for int_fastN_t / uint_fastN_t). Add support for those length modifiers (such a feature was previously requested in bug 24466). scanf support is to be added separately. GCC 13 has format checking support for these modifiers. When used with the support for registering format specifiers, these modifiers are translated to existing flags in struct printf_info, rather than trying to add some way of distinguishing them without breaking the printf_info ABI. C2x requires an error to be returned for unsupported values of N; this is implemented for printf-family functions, but the parse_printf_format interface doesn't support error returns, so such an error gets discarded by that function. Tested for x86_64 and x86.
* manual: document snprintf truncation betterPaul Eggert2023-04-081-1/+4
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* Update printf %b/%B C2x supportJoseph Myers2023-03-141-1/+1
| | | | | | | | | | | | | | | | WG14 recently accepted two additions to the printf/scanf %b/%B support: there are now PRIb* and SCNb* macros in <inttypes.h>, and printf %B is now an optional feature defined in normative text, instead of recommended practice, with corresponding PRIB* macros that can also be used to test whether that optional feature is supported. See N3072 items 14 and 15 for details (those changes were accepted, some other changes in that paper weren't). Add the corresponding PRI* macros to glibc and update one place in the manual referring to %B as recommended. (SCNb* should naturally be added at the same time as the corresponding scanf %b support.) Tested for x86_64 and x86.
* C2x scanf binary constant handlingJoseph Myers2023-03-021-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | C2x adds binary integer constants starting with 0b or 0B, and supports those constants for the %i scanf format (in addition to the %b format, which isn't yet implemented for scanf in glibc). Implement that scanf support for glibc. As with the strtol support, this is incompatible with previous C standard versions, in that such an input string starting with 0b or 0B was previously required to be parsed as 0 (with the rest of the input potentially matching subsequent parts of the scanf format string). Thus this patch adds 12 new __isoc23_* functions per long double format (12, 24 or 36 depending on how many long double formats the glibc configuration supports), with appropriate header redirection support (generally very closely following that for the __isoc99_* scanf functions - note that __GLIBC_USE (DEPRECATED_SCANF) takes precedence over __GLIBC_USE (C2X_STRTOL), so the case of GNU extensions to C89 continues to get old-style GNU %a and does not get this new feature). The function names would remain as __isoc23_* even if C2x ends up published in 2024 rather than 2023. When scanf %b support is added, I think it will be appropriate for all versions of scanf to follow C2x rules for inputs to the %b format (given that there are no compatibility concerns for a new format). Tested for x86_64 (full glibc testsuite). The first version was also tested for powerpc (32-bit) and powerpc64le (stdio-common/ and wcsmbs/ tests), and with build-many-glibcs.py.
* Document '%F' format specifierPaul Pluzhnikov2023-01-251-11/+12
| | | | | | | | | | The '%F' format specifier was implemented in commit 6c46718f9f0 on 2000-08-23, but remains undocumented in the manual. https://stackoverflow.com/questions/75157669/format-specifier-f-missing-from-glibcs-documentation Fix that. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* libio: Convert __vswprintf_internal to buffers (bug 27857)Florian Weimer2022-12-191-3/+4
| | | | | | | Always null-terminate the buffer and set E2BIG if the buffer is too small. This fixes bug 27857. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* manual: Add missing % in int conversion listJakub Wilk2022-10-251-1/+1
| | | | Signed-off-by: Jakub Wilk <jwilk@jwilk.net>
* manual: Drop obsolete @refillSiddhesh Poyarekar2022-01-121-2/+2
| | | | | | | | The @refill command has been obsolete for a while and now texinfo has started warning about it. Reviewed-by: Florian Weimer <fweimer@redhat.com> Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* stdio: Implement %#m for vfprintf and related functionsFlorian Weimer2021-12-231-2/+6
| | | | | | | | | %#m prints errno as an error constant if one is available, or a decimal number as a fallback. This intends to address the gap that strerrorname_np does not work well with printf for unknown error codes due to its NULL return values in those cases. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* Support C2X printf %b, %BJoseph Myers2021-11-101-9/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | C2X adds a printf %b format (see <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2630.pdf>, accepted for C2X), for outputting integers in binary. It also has recommended practice for a corresponding %B format (like %b, but %#B starts the output with 0B instead of 0b). Add support for these formats to glibc. One existing test uses %b as an example of an unknown format, to test how glibc printf handles unknown formats; change that to %v. Use of %b and %B as user-registered format specifiers continues to work (and we already have a test that covers that, tst-printfsz.c). Note that C2X also has scanf %b support, plus support for binary constants starting 0b in strtol (base 0 and 2) and scanf %i (strtol base 0 and scanf %i coming from a previous paper that added binary integer literals). I intend to implement those features in a separate patch or patches; as discussed in the thread starting at <https://sourceware.org/pipermail/libc-alpha/2020-December/120414.html>, they will be more complicated because they involve adding extra public symbols to ensure compatibility with existing code that might not expect 0b constants to be handled by strtol base 0 and 2 and scanf %i, whereas simply adding a new format specifier poses no such compatibility concerns. Note that the actual conversion from integer to string uses existing code in _itoa.c. That code has special cases for bases 8, 10 and 16, probably so that the compiler can optimize division by an integer constant in the code for those bases. If desired such special cases could easily be added for base 2 as well, but that would be an optimization, not actually needed for these printf formats to work. Tested for x86_64 and x86. Also tested with build-many-glibcs.py for aarch64-linux-gnu with GCC mainline to make sure that the test does indeed build with GCC 12 (where format checking warnings are enabled for most of the test).
* Add C2X _PRINTF_NAN_LEN_MAXJoseph Myers2021-09-301-1/+4
| | | | | | | | | | | | | | C2X adds a macro _PRINTF_NAN_LEN_MAX to <stdio.h>, giving the maximum length of printf output for a NaN. glibc never includes an n-char-sequence in its printf output for NaNs, so the correct value for glibc is 4 ("-nan" or "-NAN"); define the macro accordingly. This patch makes the macro definition conditional on __GLIBC_USE (ISOC2X), as is generally done with features from new standard versions. The name is in the implementation namespace for older standards, so it would also be possible to define it unconditionally. Tested for x86_64.
* Improve documentation for malloc etc. (BZ#27719)Paul Eggert2021-04-131-16/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cover key corner cases (e.g., whether errno is set) that are well settled in glibc, fix some examples to avoid integer overflow, and update some other dated examples (code needed for K&R C, e.g.). * manual/charset.texi (Non-reentrant String Conversion): * manual/filesys.texi (Symbolic Links): * manual/memory.texi (Allocating Cleared Space): * manual/socket.texi (Host Names): * manual/string.texi (Concatenating Strings): * manual/users.texi (Setting Groups): Use reallocarray instead of realloc, to avoid integer overflow issues. * manual/filesys.texi (Scanning Directory Content): * manual/memory.texi (The GNU Allocator, Hooks for Malloc): * manual/tunables.texi: Use code font for 'malloc' instead of roman font. (Symbolic Links): Don't assume readlink return value fits in 'int'. * manual/memory.texi (Memory Allocation and C, Basic Allocation) (Malloc Examples, Alloca Example): * manual/stdio.texi (Formatted Output Functions): * manual/string.texi (Concatenating Strings, Collation Functions): Omit pointer casts that are needed only in ancient K&R C. * manual/memory.texi (Basic Allocation): Say that malloc sets errno on failure. Say "convert" rather than "cast", since casts are no longer needed. * manual/memory.texi (Basic Allocation): * manual/string.texi (Concatenating Strings): In examples, use C99 declarations after statements for brevity. * manual/memory.texi (Malloc Examples): Add portability notes for malloc (0), errno setting, and PTRDIFF_MAX. (Changing Block Size): Say that realloc (p, 0) acts like (p ? (free (p), NULL) : malloc (0)). Add xreallocarray example, since other examples can use it. Add portability notes for realloc (0, 0), realloc (p, 0), PTRDIFF_MAX, and improve notes for reallocating to the same size. (Allocating Cleared Space): Reword now-confusing discussion about replacement, and xref "Replacing malloc". * manual/stdio.texi (Formatted Output Functions): Don't assume message size fits in 'int'. * manual/string.texi (Concatenating Strings): Fix undefined behavior involving arithmetic on a freed pointer.
* manual: clarify that scanf %n supports type modifiersAlyssa Ross2021-03-301-5/+6
| | | | | | | | | | My initial reading of the %n documentation was that it didn't support type conversions, because it only mentioned int*. Corresponding man-pages patch: https://lore.kernel.org/linux-man/20210328215509.31666-1-hi@alyssa.is/ Reviewed-by: Arjun Shankar <arjun@redhat.com>
* manual: Fix typo in parse_printf_format example [BZ #24638]Girish Joshi2020-03-041-1/+1
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* manual: clarify fopen with the x flagPaul Eggert2019-12-111-1/+3
| | | | | * manual/stdio.texi (Opening Streams): Say how glibc's implementation of fopen with "x" follows ISO C11.
* Document interaction with GCC built-ins in the Customizing PrintfMartin Sebor2018-06-291-4/+12
| | | | section of the manual.
* Remove macros extend_alloca, extend_alloca_account [BZ #18023]Florian Weimer2018-06-271-1/+0
| | | | | The unused macro definition in posix/glob.c comes from gnulib and will have to be removed there.
* manual: Fix Texinfo warnings about improper node names.Rical Jasan2018-02-091-4/+4
| | | | | | | | | | | | | | | A number of cross-references to the GCC info manual cause Texinfo warnings; e.g.: ./creature.texi:11: warning: @xref node name should not contain `.' This is due to "gcc.info" being used in the INFO-FILE-NAME (fourth) argument. Changing it to "gcc" removes these warnings. (Manually confirmed equivalent behaviour for make info, html, and pdf.) * manual/creature.texi: Convert references to gcc.info to gcc. * manual/stdio.texi: Likewise. * manual/string.texi: Likewise.
* manual: Replace summary.awk with summary.pl.Rical Jasan2017-06-151-330/+165
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The Summary is now generated from @standards, and syntax-checking is performed. If invalid @standards syntax is detected, summary.pl will fail, reporting all errors. Failure and error reporting is disabled for now, however, since much of the manual is still incomplete wrt. header and standards annotations. Note that the sorting order of the Summary has changed; summary.pl respects the locale, like summary.awk did, but the use of LC_ALL=C is introduced in the Makefile. Other notable deviations are improved detection of the annotated elements' names, which are used for sorting, and improved detection of the @node used to reference into the manual. The most noticeable difference in the rendered Summary is that entries may now contain multiple lines, one for each header and standard combination. summary.pl accepts a `--help' option, which details the expected syntax of @standards. If errors are reported, the user is directed to this feature for further information. * manual/Makefile: Generate summary.texi with summary.pl. Force use of the C locale. Update Perl dependency comment. * manual/header.texi: Update reference to summary.awk. * manual/macros.texi: Refer authors to `summary.pl --help'. * manual/summary.awk: Remove file. * manual/summary.pl: New file. Generate summary.texi, and check for @standards-related syntax errors. * manual/argp.texi: Convert header and standards @comments to @standards. * manual/arith.texi: Likewise. * manual/charset.texi: Likewise. * manual/conf.texi: Likewise. * manual/creature.texi: Likewise. * manual/crypt.texi: Likewise. * manual/ctype.texi: Likewise. * manual/debug.texi: Likewise. * manual/errno.texi: Likewise. * manual/filesys.texi: Likewise. * manual/getopt.texi: Likewise. * manual/job.texi: Likewise. * manual/lang.texi: Likewise. * manual/llio.texi: Likewise. * manual/locale.texi: Likewise. * manual/math.texi: Likewise. * manual/memory.texi: Likewise. * manual/message.texi: Likewise. * manual/pattern.texi: Likewise. * manual/pipe.texi: Likewise. * manual/process.texi: Likewise. * manual/resource.texi: Likewise. * manual/search.texi: Likewise. * manual/setjmp.texi: Likewise. * manual/signal.texi: Likewise. * manual/socket.texi: Likewise. * manual/startup.texi: Likewise. * manual/stdio.texi: Likewise. * manual/string.texi: Likewise. * manual/sysinfo.texi: Likewise. * manual/syslog.texi: Likewise. * manual/terminal.texi: Likewise. * manual/threads.texi: Likewise. * manual/time.texi: Likewise. * manual/users.texi: Likewise.
* libio: Avoid dup already opened file descriptor [BZ#21393]Adhemerval Zanella2017-05-221-1/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As described in BZ#21398 (close as dup of 21393) report current freopen implementation fails when one tries to freopen STDIN_FILENO, STDOUT_FILENO, or STDERR_FILENO. Although on bug report the discussion leads to argue if a close followed by a freopen on the standard file is a valid operation, the underlying issue is not really the check for dup3 returned value, but rather calling it if the returned file descriptor is equal as the input one. So for a quality of implementation this patch avoid calling dup3 for the aforementioned case. It also adds a dup3 error case check for the two possible failures, with one being Linux only: EINTR and EBUSY. The EBUSY issue is better explained on this stackoverflow thread [1], but in a short it is due the internal Linux implementation which allows a race condition window for dup2 due the logic dissociation of file descriptor allocation and actual VFS 'install' operation. For both outliers failures all allocated memory is freed and a NULL FILE* is returned. With this patch the example on BZ#21398 is now actually possible (I used as the testcase for the bug report). Checked on x86_64-linux-gnu. [BZ #21393] * libio/freopen.c (freopen): Avoid dup already opened file descriptor and add a check for dup3 failure. * libio/freopen64.c (freopen64): Likewise. * libio/tst-freopen.c (do_test): Rename to do_test_basic and use libsupport. (do_test_bz21398): New test. * manual/stdio.texi (freopen): Add documentation of EBUSY failure. [1] http://stackoverflow.com/questions/23440216/race-condition-when-using-dup2
* manual: Convert @tables of variables to @vtables.Rical Jasan2016-12-211-5/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Texinfo @vindex commands add entries to the Variable and Constant Macro Index. Similarly, @items in @vtables are automatically indexed. A number of @tables exist where all @items are @vindexed or all @items are variables, but not indexed, suggesting an optimization by converting such @tables to @vtables and dropping the @vindex. Using a @vtable provides a context for processing @items whereby it can be known the @items should have header and standards annotations. This commit converts @tables of such @items to @vtables in order to establish a framework for automated processing. A pleasant consequence of these changes is that @items previously lacking a @vindex are present in the Variable and Constant Macro Index now. @vindex entries previously detected by summary.awk will still be detected as @items with appropriate annotations. The @vtable of the NSS databases is converted to a @table because 1) those @items are not variables (and will no longer appear in the Variable and Constant Macro Index) and 2) they do not need header and standards annotations, so the incorrect context is fixed. * manual/nss.texi: Change incorrect @vtable to @table. * manual/arith.texi: Convert @tables of variables to @vtables and remove unnecessary indexing. * manual/filesys.texi: Likewise. * manual/llio.texi: Likewise. * manual/memory.texi: Likewise. * manual/process.texi: Likewise. * manual/resource.texi: Likewise. * manual/search.texi: Likewise. * manual/signal.texi: Likewise. * manual/socket.texi: Likewise. * manual/stdio.texi: Likewise. * manual/sysinfo.texi: Likewise. * manual/syslog.texi: Likewise. * manual/terminal.texi: Likewise. * manual/time.texi: Likewise. * manual/users.texi: Likewise.
* Manual typos: Input/Output on StreamsRical Jasan2016-10-061-41/+42
| | | | | | 2016-05-06 Rical Jasan <ricaljasan@pacific.net> * manual/stdio.text: Fix typos in the manual.
* Split large string section; add truncation advicePaul Eggert2015-12-101-1/+1
| | | | | | | | | | | | * manual/examples/strncat.c: Remove. This example was misleading, as the code would have undefined behavior if "hello" was longer than SIZE. Anyway, the manual shouldn't encourage strncpy+strncat for this sort of thing. * manual/string.texi (Copying Strings and Arrays): Split into three sections Copying Strings and Arrays, Concatenating Strings, and Truncating Strings, as this section was way too long. All cross-referenced changed. Add advice about string-truncation functions. Remove misleading strncat example.
* The va_list pointer is unspecified after a call to vfprintf [BZ #18982]Florian Weimer2015-10-171-14/+10
| | | | This adjusts the documentation to the existing implementation.
* Fix exponents in manual.Ondřej Bílka2015-08-201-4/+4
| | | | | | | * manual/macros.texi: Add twoexp macro. * manual/filesys.texi: Fix exponents. * manual/llio.texi: Likewise. * manual/stdio.texi: Likewise.
* Fix types of stream hook functions in manual.Ondřej Bílka2014-04-281-4/+4
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* manual: clarify buffer behavior in getline [BZ #5666]David Svoboda2014-04-031-1/+2
| | | | | | | | | | | If the user has requested automatic buffer creation, getline may create it and not free things when an error occurs. That means the user is always responsible for calling free() regardless of the return value. The current documentation does not explicitly cover this which leaves it slightly ambiguous to the reader. So clarify things. URL: https://sourceware.org/bugzilla/show_bug.cgi?id=5666
* Fix two spaces after sentence.Ondřej Bílka2014-02-261-2/+2
| | | | | Minor formatting fix that was carried by issuing sed -e"s/\. \([A-Z]\)/. \1/" followed by editing result.
* * manual/stdio.texi: Document MTASC-safety properties.Alexandre Oliva2014-02-011-0/+249
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* Fix spelling in manual, as in bug 16376Ville Skytta2013-12-301-2/+2
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* Clarify that scanf does not use character classes. Fixes bug 12986Ondřej Bílka2013-12-231-1/+5
| | | | | Update documentation to say that scanf ("%[[:alpha:]]", c) does not read alphabetic characters but is parsed literarily.
* Fix then/than typos.Ondřej Bílka2013-08-301-1/+1
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* Fix some errors in declarations in the manual.Roland McGrath2013-02-111-2/+2
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* Remove @hsep and @vsep usage from info pagesAllan McRae2012-12-041-1/+1
| | | | These cause an error when the info pages are build with texinfo>=4.13.90.
* * manual/stdio.texi (snprintf): Clarify handling of the trailingJeff Law2012-08-131-0/+2
| | | | null byte in the output string.
* Fix description of user provided write functionPetr Baudis2012-04-121-1/+2
| | | | | | [BZ #2074] * stdio.texi (Hook Functions): The user provided writer function is not allowed to return -1.
* Document additional fopen optionsAndreas Jaeger2012-04-091-7/+25
| | | | | | [BZ #10254] The manual failed to explain the new (the first were introduced with glibc 2.3 or so) parameters to fopen.
* Clean up glibc manual references to "GNU system" (bug 6911).Joseph Myers2012-03-081-9/+9
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* Use Texinfo macros to refer to the GNU C Library within the manual.Joseph Myers2012-02-281-27/+27
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* Fix various problems with @deftypefun lines.Nicolas Boulenguez2012-02-171-1/+2
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* Fix typos in documentation of fopen ",ccs=STRING".Joseph Myers2012-02-171-2/+2
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* Remove mention of open_obstack_stream, which has never existed in libio.Roland McGrath2011-10-261-59/+0
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* Fix manual regarding switch from read to write on streams.Per Inge Mathisen2011-05-111-66/+64
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* Remove doubled words.Jim Meyering2011-04-221-1/+1
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* manual: fix doubled-words and typosJim Meyering2010-02-221-1/+1
| | | | | | | | | | | * manual/charset.texi (Selecting the Conversion): Likewise. * manual/errno.texi (Error Messages): Likewise. * manual/getopt.texi (Getopt Long Options): Likewise. * manual/memory.texi (Resizing the Data Segment): Likewise. * manual/message.texi (GUI program problems): Likewise. * manual/resource.texi (CPU Affinity): Likewise. * manual/stdio.texi (Streams and Threads): Likewise. * manual/time.texi (High Accuracy Clock): Likewise.
* [BZ #5222]Ulrich Drepper2007-10-281-1/+1
| | | | | | | 2007-10-28 Ulrich Drepper <drepper@redhat.com> [BZ #5222] * elf/dl-load.c (_dl_rtld_di_serinfo): Correct handling of short path elements in counting mode.
* * manual/stdio.texi (Variable Arguments Output): Fix xref to gcc manual.Roland McGrath2007-08-121-3/+2
| | | | From: Karl Berry <karl@freefriends.org>.
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