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10.46.65 strtod ¶

POSIX specification:
https://pubs.opengroup.org/onlinepubs/9799919799/functions/strtod.html

Gnulib module: strtod or strtod-obsolete

Portability problems fixed by either Gnulib module strtod or strtod-obsolete:

• This function mis-parses strings with leading ‘+’ on some old platforms: Old versions of Linux.
• This function returns a wrong end pointer on some old platforms.
• This function allows whitespace between ‘e’ and the exponent on some platforms: HP-UX 11.11.
• This function returns the wrong end pointer for ‘-0x’ on some platforms: glibc 2.4, Mac OS X 10.5, FreeBSD 6.2, AIX 7.1, Cygwin < 1.5.25-11.
• This function fails to parse Infinities and plain NaNs on some platforms: OpenBSD 4.0, HP-UX 11.11, Solaris 9, mingw, MSVC 14.
• This function fails to parse ‘NaN()’ on some platforms: glibc 2.3.6, Mac OS X 10.5, FreeBSD 6.2, OpenBSD 4.0, AIX 7.1, HP-UX 11.11, Cygwin < 1.5.25-11, mingw, MSVC 14.
• This function fails to parse ‘NaN(n-char-sequence)’ on some platforms: OpenBSD 4.0, HP-UX 11.11, mingw, MSVC 14.
• This function parses ‘NaN(n-char-sequence)’, but returns the wrong end pointer on some platforms: glibc 2.4, AIX 7.1.
• This function misparses ‘nan(’ on some platforms: macOS 10.6.6.
• This function fails to parse C99 hexadecimal floating point on some platforms: NetBSD 5.0, OpenBSD 4.0, AIX 5.1, HP-UX 11.11, Solaris 11.4, mingw, MSVC 14.
• In hexadecimal floats, this function allows whitespace between ‘p’ and the exponent on some platforms: HP-UX 11.31/ia64.
• This function returns the wrong end pointer for ‘0x1p’ on some platforms: AIX 7.1.
• This function fails to set errno upon gradual underflow (resulting in a denormalized number) on some platforms: Cygwin 2.9.

Portability problems fixed by Gnulib module strtod-obsolete:

• This function is missing on some old platforms.

Portability problems not fixed by Gnulib:

• This function returns +0.0 (not −0.0) for negative underflow on some platforms: glibc 2.7, Cygwin 1.5.x, mingw, MSVC 14.
• This function cannot distinguish between “nan” and “-nan” on some platforms: glibc 2.7, mingw, MSVC 14.
• This function fails to correctly parse very long strings on some platforms: Mac OS X 10.5, FreeBSD 6.2, NetBSD 5.0, OpenBSD 4.0, Cygwin, mingw, MSVC 14.
• This function fails to set errno upon gradual underflow (resulting in a denormalized number) on some platforms: MSVC 14.
• The replacement function does not always return correctly rounded results.
• If no conversion could be performed, this function sets errno to EINVAL on some platforms. Portable programs should check for no conversion by comparing str to *endptr, not by inspecting errno.