f7ff515961
* Fix reading the same symbol twice when using `{f,}scanf()`
PR #924 appears to use `unget()` subtly incorrectly when parsing
floating point numbers. The rest of the code only uses `unget()`
immediately followed by `goto Done;` to return back the symbol that
can't possibly belong to the directive we're processing.
With floating-point, however, the ungot characters could very well
be valid for the *next* directive, so we will essentially read them
twice. It can't be seen in `sscanf()` tests because `unget()` is a
no-op there, but the test I added for `fscanf()` fails like this:
...
EXPECT_EQ(0xDEAD, i1)
need 57005 (or 0xdead) =
got 908973 (or 0x000ddead)
...
EXPECT_EQ(0xBEEF, i2)
need 48879 (or 0xbeef) =
got 769775 (or 0x000bbeef)
This means we read 0xDDEAD instead of 0xDEAD and 0xBBEEF instead of
0xBEEF. I checked that both musl and glibc read 0xDEAD/0xBEEF, as
expected.
Fix the failing test by removing the unneeded `unget()` calls.
* Don't read invalid floating-point numbers in `*scanf()`
Currently, we just ignore any errors from `strtod()`. They can
happen either because no valid float can be parsed at all, or
because the state machine recognizes only a prefix of a valid
floating-point number.
Fix this by making sure `strtod()` parses everything we recognized,
provided it's non-empty. This requires to pop the last character
off the FP buffer, which is supposed to be parsed by the next
`*scanf()` directive.
* Make `%c` parsing in `*scanf()` respect the C standard
Currently, `%c`-style directives always succeed even if there
are actually fewer characters in the input than requested.
Before the fix, the added test fails like this:
...
EXPECT_EQ(2, sscanf("ab", "%c %c %c", &c2, &c3, &c4))
need 2 (or 0x02 or '\2' or ENOENT) =
got 3 (or 0x03 or '\3' or ESRCH)
...
EXPECT_EQ(0, sscanf("abcd", "%5c", s2))
need 0 (or 0x0 or '\0') =
got 1 (or 0x01 or '\1' or EPERM)
musl and glibc pass this test.
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| .. | ||
| calls | ||
| crt | ||
| dlopen | ||
| elf | ||
| fmt | ||
| integral | ||
| intrin | ||
| irq | ||
| isystem | ||
| log | ||
| mem | ||
| nexgen32e | ||
| nt | ||
| proc | ||
| runtime | ||
| sock | ||
| stdio | ||
| str | ||
| sysv | ||
| testlib | ||
| thread | ||
| time | ||
| tinymath | ||
| vga | ||
| x | ||
| ar.h | ||
| assert.h | ||
| atomic.h | ||
| BUILD.mk | ||
| complex.h | ||
| cosmo.h | ||
| cxxabi.h | ||
| dce.h | ||
| dos.internal.h | ||
| empty.s | ||
| errno.h | ||
| imag.internal.h | ||
| inttypes.h | ||
| iso646.internal.h | ||
| limits.h | ||
| literal.h | ||
| mach.internal.h | ||
| macho.internal.h | ||
| macros.internal.h | ||
| math.h | ||
| paths.h | ||
| README.md | ||
| serialize.h | ||
| stdalign.internal.h | ||
| stdbool.h | ||
| stdckdint.h | ||
| stdlib.h | ||
| temp.h | ||
| testlib-test.txt | ||
| type2str.h | ||
| zip.internal.h | ||
Cosmopolitan Standard Library
This directory defines static archives defining functions, like
printf(), mmap(), win32, etc. Please note that the Cosmopolitan
build configuration doesn't link any C/C++ library dependencies
by default, so you still have the flexibility to choose the one
provided by your system. If you'd prefer Cosmopolitan, just add
$(LIBC) and $(CRT) to your linker arguments.
Your library is compromised of many bite-sized static archives. We use the checkdeps tool to guarantee that the contents of the archives are organized in a logical way that's easy to use with or without our makefile infrastructure, since there's no cyclic dependencies.
The Cosmopolitan Library exports only the most stable canonical
system calls for all supported operating systems, regardless of
which platform is used for compilation. We polyfill many of the
APIs, e.g. read(), write() so they work consistently everywhere
while other apis, e.g. CreateWindowEx(), might only work on one
platform, in which case they become no-op functions on others.
Cosmopolitan polyfill wrappers will usually use the dollar sign naming convention, so they may be bypassed when necessary. This same convention is used when multiple implementations of string library and other performance-critical function are provided to allow Cosmopolitan to go fast on both old and newer computers.
We take an approach to configuration that relies heavily on the
compiler's dead code elimination pass (libc/dce.h). Most of the
code is written so that, for example, folks not wanting support
for OpenBSD can flip a bit in SUPPORT_VECTOR and that code will
be omitted from the build. The same is true for builds that are
tuned using -march=native which effectively asks the library to
not include runtime support hooks for x86 processors older than
what you use.
Please note that, unlike Cygwin or MinGW, Cosmopolitan does not achieve broad support by bolting on a POSIX emulation layer. We do nothing more than (in most cases) stateless API translations that get you 90% of the way there in a fast lightweight manner. We therefore can't address some of the subtle differences, such as the nuances of absolute paths on Windows. Our approach could be compared to something more along the lines of, "the Russians just used a pencil to write in space", versus spending millions researching a pen like NASA.