Guardian Native C Library Calls Reference Manual (G06.29+, H06.08+, J06.03+)

strtof(3) Guardian Native C Library Calls Reference Manual
NAME
strtof - Converts a character string to a floating-point value
LIBRARY
H-series and J-series native Guardian processes: $SYSTEM.ZDLLnnn.ZCRTLDLL
32-bit H-series and J-series OSS processes: /G/system/zdllnnn/zcrtldll
64-bit H-series and J-series OSS processes: /G/system/zdllnnn/ycrtldll
SYNOPSIS
#include <stdlib.h>
float strtof(
const char *nptr,
char **endptr
);
PARAMETERS
nptr Points to the character string to be converted.
endptr Points to a pointer in which the strtof() function stores the position in the string
specified by the nptr parameter where an invalid character is found.
DESCRIPTION
The strtof() function converts the initial portion of the string pointed to by the nptr parameter to
a floating-point value. First the input string is decomposed into the following three parts:
• An initial, possibly empty, sequence of white-space characters (as specified by the
isspace() function for programs in the C/POSIX locale and the iswspace() function for
programs in other locales).
• A subject sequence interpreted as a floating-point constant.
• A final string of one or more unrecognized characters, including the terminating null byte
of the input string.
After decomposition of the string, the subject sequence is converted to a floating-point number,
and the resulting value is returned. A subject sequence is defined as the longest initial subse-
quence of the input string, starting with the first non-white-space character, that is of the
expected form.
The expected form and order of the subject sequence is an optional + (plus) or - (minus) sign,
followed by one of these:
• A nonempty sequence of decimal digits optionally containing a radix (decimal-point)
character, then an optional exponent part, which consists of e or E, followed by an
optional + (plus sign) or - (minus sign), followed by one or more decimal digits.
• A 0x or 0X, then a nonempty sequence of hexadecimal digits optionally containing a
radix (decimal-point) character, then an optional binary exponent part, which consists of
p or P, followed by an optional + (plus sign) or - (minus sign), followed by one or more
decimal digits.
• For IEEE floating-point values only, one of INF, INFINITY, NAN, or NAN(seq), where
seq is a sequence of digit and nondigit characters.
When the input string is empty or consists entirely of white space, or when the first non-white-
space character is not a sign, a digit, or a radix character, the subject sequence contains no char-
acters.
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