cosmopolitan/libc/stdio/printf.c

73 lines
4.0 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/stdio/stdio.h"
/**
* Formats and writes string to stdout.
*
* Cosmopolitan supports most of the standard formatting behaviors
* described by `man 3 printf`, in addition to the following:
*
* - %jd, %jx, etc. are {,u}intmax_t which in Cosmopolitan is 128-bit.
*
* - %'d or %,d may be used to insert thousands separators. The prior is
* consistent with C; the latter is consistent with Python.
*
* - %m inserts strerror(errno) into the formatted output. This is
* consistent with glibc, musl, and uclibc.
*
* - %n inserts "\n" on non-Windows and "\r\n" on Windows. This is the
* same behavior as Java. It's incompatible with glibc's behavior,
* since that's problematic according to Android's security team.
*
* - %hs converts UTF-16/UCS-2 → UTF-8, which can be helpful on Windows.
* Formatting (e.g. %-10hs) will use monospace display width rather
* than string length or codepoint count.
*
* - %ls (or %Ls) converts UTF-32 → UTF-8. Formatting (e.g. %-10ls) will
* use monospace display width rather than string length.
*
* - The %#s and %#c alternate forms display values using the standard
* IBM standard 256-letter alphabet. Using %#.*s to specify length
* will allow true binary (i.e. with NULs) to be formatted.
*
* - The %'s and %'c alternate forms are Cosmopolitan extensions for
* escaping string literals for C/C++ and Python. The outer quotation
* marks can be added automatically using %`s. If constexpr format
* strings are used, we can avoid linking cescapec() too.
*
* - The backtick modifier (%`s and %`c) and repr() directive (%r) both
* ask the formatting machine to represent values as real code rather
* than using arbitrary traditions for displaying values. This means
* it implies the quoting modifier, wraps the value with {,u,L}['"]
* quotes, displays NULL as "NULL" rather than "(null)", etc.
*
* @see palandprintf() for intuitive reference documentation
* @see {,v}{,s{,n},{,{,x}as},f,d}printf
*/
int(printf)(const char* fmt, ...) {
int rc;
va_list va;
va_start(va, fmt);
rc = (vfprintf)(stdout, fmt, va);
va_end(va);
return rc;
}