atof(2) [plan9 man page]

ATOF(2) 							System Calls Manual							   ATOF(2)

NAME

       atof, atoi, atol, charstod, strtod, strtol, strtoul - convert text to numbers

SYNOPSIS

       #include <u.h>
       #include <libc.h>

       double atof(char *nptr)

       int    atoi(char *nptr)

       long   atol(char *nptr)

       double charstod(int (*f)(void *), void *a)

       double strtod(char *nptr, char **rptr)

       long   strtol(char *nptr, char **rptr, int base)

       ulong  strtoul(char *nptr, char **rptr, int base)

       /* Alef only */

       int    strtoi(byte *nptr, byte **rptr, int base)

       uint   strtoui(byte *nptr, byte **rptr, int base)

       float  strtof(byte *nptr, byte **rptr);

DESCRIPTION

       Atof,  atoi,  and  atol	convert a string pointed to by nptr to floating, integer, and long integer representation respectively.  The first
       unrecognized character ends the string.	Leading C escapes are understood, as in strtol with base zero.

       Atof recognizes an optional string of tabs and spaces, then an optional sign, then a string  of	digits	optionally  containing	a  decimal
       point, then an optional or followed by an optionally signed integer.

       Atoi and atol recognize an optional string of tabs and spaces, then an optional sign, then a string of decimal digits.

       Strtod,	strtol,  and strtoul behave similarly to atof and atol and, if rptr is not zero, set *rptr to point to the input character immedi-
       ately after the string converted.

       Strtol and strtoul interpret the digit string in the specified base, from 2 to 36, each digit being less than the base.	Digits with  value
       over  9	are represented by letters, a-z or A-Z.  If base is 0, the input is interpreted as an integral constant in the style of C (with no
       suffixed type indicators): numbers are octal if they begin with hexadecimal if they begin with or otherwise decimal.  Strtoul does not rec-
       ognize signs.

       Charstod  interprets floating point numbers like atof, but it gets successive characters by calling (*f)(a).  The last call to f terminates
       the scan, so it must have returned a character that is not a legal continuation of a number.  Therefore, it may be necessary to back up the
       input stream one character after calling charstod.

   Alef
       The  routines  strtol  and  strtoul  are  renamed strtoi and strtoui and return type int and uint.  There is no charstod or atof.  Instead,
       strtof is like a floating-point base 10 strtoi.

SOURCE

       /sys/src/libc/port

SEE ALSO

       fscanf(2)

DIAGNOSTICS

       Zero is returned if the beginning of the input string is not interpretable as a number; even in this case, rptr will be updated.
       These routines set errstr.

BUGS

       Atoi and atol accept octal and hexadecimal numbers in the style of C, contrary to the ANSI specification.

																	   ATOF(2)

Check Out this Related Man Page

ATOI(3)                                                      Linux Programmer's Manual                                                     ATOI(3)

NAME

       atoi, atol, atoll - convert a string to an integer

SYNOPSIS

       #include <stdlib.h>

       int atoi(const char *nptr);
       long atol(const char *nptr);
       long long atoll(const char *nptr);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       atoll():
           __ISOC99_SOURCE ||
               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION

       The atoi() function converts the initial portion of the string pointed to by nptr to int.  The behavior is the same as

           strtol(nptr, NULL, 10);

       except that atoi() does not detect errors.

       The atol() and atoll() functions behave the same as atoi(), except that they convert the initial portion of the string to their return type
       of long or long long.

RETURN VALUE

       The converted value.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       +------------------------+---------------+----------------+
       |Interface               | Attribute     | Value          |
       +------------------------+---------------+----------------+
       |atoi(), atol(), atoll() | Thread safety | MT-Safe locale |
       +------------------------+---------------+----------------+
CONFORMING TO

       POSIX.1-2001, POSIX.1-2008, C99, SVr4, 4.3BSD.  C89 and POSIX.1-1996 include the functions atoi() and atol() only.

NOTES

       Linux libc provided atoq() as an obsolete name for atoll(); atoq() is not provided by glibc.

SEE ALSO

       atof(3), strtod(3), strtol(3), strtoul(3)

COLOPHON

       This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

GNU                                                                 2016-03-15                                                             ATOI(3)

Linux and UNIX Man Pages

atof(2) [plan9 man page]

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