Standard C Library Functions string_to_decimal(3C)
NAME
string_to_decimal, file_to_decimal, func_to_decimal - parse
characters into decimal recordSYNOPSIS
#include
void string_to_decimal(char **pc, int nmax,
int fortran_conventions, decimal_record *pd,
enum decimal_string_form *pform, char **pechar);
void func_to_decimal(char **pc, int nmax,
int fortran_conventions, decimal_record *pd,
enum decimal_string_form *pform, char **pechar,
int (*pget)(void), int *pnread, int (*punget)(int c));#include
void file_to_decimal(char **pc, int nmax,
int fortran_conventions, decimal_record *pd,
enum decimal_string_form *pform, char **pechar,
FILE *pf, int *pnread);DESCRIPTION
These functions attempt to parse a numeric token from at most nmax characters read from a string **pc, a file *pf, or function (*pget). They set the decimal record *pd to reflect the value of the numeric token recognized and set *pform and *pechar to indicate its form.The accepted forms for the numeric token consist of an ini-
tial, possibly empty, sequence of white-space characters, as
defined by isspace(3C), followed by a subject sequence representing a numeric value, infinity, or NaN. The subject sequence consists of an optional plus or minus sign followed by one of the following:o a non-empty sequence of decimal digits optionally
containing a decimal point character, then an optional exponent part o one of INF or INFINITY, ignoring case o one of NAN or NAN(string), ignoring case in the NAN part; string can be any sequence of characters not containing ')' (right parenthesis) or '\0' (null).SunOS 5.11 Last change: 1 Oct 2003 1
Standard C Library Functions string_to_decimal(3C)
The fortran_conventions argument provides additional control
over the set of accepted forms. It must be one of the fol-
lowing values: 0 no Fortran conventions1 Fortran list-directed input conventions
2 Fortran formatted input conventions, blanks are ignored3 Fortran formatted input conventions, blanks are inter-
preted as zeroesWhen fortran_conventions is zero, the decimal point charac-
ter is the current locale's decimal point character, and the exponent part consists of the letter E or e followed by anoptional sign and a non-empty string of decimal digits.
When fortran_conventions is non-zero, the decimal point
character is "." (period), and the exponent part consists ofeither a sign or one of the letters E, e, D, d, Q, or q fol-
lowed by an optional sign, then a non-empty string of
decimal digits.When fortran_conventions is 2 or 3, blanks can appear in the
digit strings for the integer, fraction, and exponent parts, between the exponent delimiter and optional exponent sign, and after an INF, INFINITY, NAN, or NAN(string). Whenfortran_conventions is 2, all blanks are ignored. When
fortran_conventions is 3, blanks in digit strings are inter-
preted as zeros and other blanks are ignored. The following table summarizes the accepted forms and showsthe corresponding values to which *pform and pd->fpclass are
set. Here digits represents any string of decimal digits, "." (period) stands for the decimal point character, and exponent represents the exponent part as defined above. Numbers in brackets refer to the notes following the table.form *pform pd->fpclass
______________________________________________________________________
all white space [1] whitespace_form fp_zero
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Standard C Library Functions string_to_decimal(3C)
digits fixed_int_form fp_normal [2]
digits. fixed_intdot_form fp_normal [2]
.digits fixed_dotfrac_form fp_normal [2]
digits.digits fixed_intdotfrac_form fp_normal [2]
digits exponent floating_int_form fp_normal [2]
digits. exponent floating_intdot_form fp_normal [2]
.digits exponent floating_dotfrac_form fp_normal [2]
digits.digits exponent floating_intdotfrac_form fp_normal [2]
INF inf_form fp_infinity
INFINITY infinity_form fp_infinity
NAN nan_form fp_quiet
NAN(string) nanstring_form fp_quiet
none of the above invalid_form fp_signaling
Notes:1. The whitespace_form is accepted only when
fortran_conventions is 2 or 3 and is interpreted as
zero.2. For all numeric forms, pd->fpclass is set to
fp_normal if any non-zero digits appear in the
integer or fraction parts, and otherwise pd-
>fpclass is set to fp_zero.
If the accepted token has one of the numeric forms andrepresents a non-zero number x, its significant digits are
stored in pd->ds. Leading and trailing zeroes and the radix
point are omitted. pd->sign and pd->exponent are set so
that if m is the integer represented by pd->ds,
-1**(pd->sign) * m * 10**(pd->exponent)
approximates x to at least 511 significant digits. pd->more
is set to 1 if this approximation is not exact (that is, theaccepted token contains additional non-zero digits beyond
those copied to pd->ds) and to 0 otherwise.
If the accepted token has the NAN(string) form, up to 511characters from the string part are copied to pd->ds.
pd->ds is always terminated by a null byte, and pd->ndigits
is set to the length of the string stored in pd->ds.
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Standard C Library Functions string_to_decimal(3C)
On entry, *pc points to the beginning of a character stringbuffer. The string_to_decimal() function reads characters
from this buffer until either enough characters are read to delimit the accepted token (for example, a null character marking the end of the string is found) or the limit of nmaxcharacters is reached. The file_to_decimal() function reads
characters from the file *pf and stores them in the buffer.The func_to_decimal() function reads characters one at a
time by calling the function (*pget)() and stores them in the buffer; (*pget)() must return integer values in therange -1 to 255, where -1 is interpreted as EOF and 0, ...,
255 are interpreted as unsigned char values. Bothfile_to_decimal() and func_to_decimal() read characters
until either enough characters are read to delimit the accepted token, EOF is encountered, or the limit of nmax characters is reached. These functions, therefore, typically read one or more additional characters beyond the end of theaccepted token and attempt to push back any excess charac-
ters read. Provided that the punget argument is not NULL,func_to_decimal() pushes back characters one at a time by
calling (*punget)(c), where c is an integer in the range 0 to 255 corresponding to a value previously read via (*pget)(). After pushing back as many excess characters aspossible, file_to_decimal() and func_to_decimal() store a
null byte in the buffer following the last character readand not pushed back and set *pnread to the number of charac-
ters stored in the buffer prior to this null byte. Since these functions can read up to nmax characters, the buffer must be large enough to hold nmax + 1. On exit, *pc points to the next character in the buffer past the last one that was accepted as part of the numeric token. If no valid token is found, *pc is unchanged. Iffile_to_decimal() and func_to_decimal() successfully push
back all unused characters, *pc points to the null byte stored in the buffer following the last character read and not pushed back. If the accepted token contains an exponent part, *pechar is set to point to the position in the buffer where the first character of the exponent field is stored. If the accepted token does not contain an exponent part, *pechar is set to NULL.USAGE
If the _IOWRT flag is set in *pf, file_to_decimal() reads
characters directly from the file buffer until a null char-
acter is found. (The _IOWRT flag should only be set when
file_to_decimal() is called from sscanf(3C).) Otherwise,
file_to_decimal() uses getc_unlocked(3C), so it is not MT-
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Standard C Library Functions string_to_decimal(3C)
safe unless the caller holds the stream lock.ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| MT-Level | MT-Safe with exceptions |
|_____________________________|_____________________________|
SEE ALSO
ctype(3C), decimal_to_floating(3C), getc_unlocked(3C),
isspace(3C), localeconv(3C), scanf(3C), setlocale(3C), strtod(3C), ungetc(3C), attributes(5)SunOS 5.11 Last change: 1 Oct 2003 5