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STRTOL(3P)                 POSIX Programmer's Manual                STRTOL(3P)
PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the  corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.
NAME
       strtol, strtoll -- convert a string to a long integer
SYNOPSIS
       #include <stdlib.h>
       long strtol(const char *restrict str, char **restrict endptr, int base);
       long long strtoll(const char *restrict str, char **restrict endptr,
           int base)
DESCRIPTION
       The functionality described on this reference page is aligned with  the
       ISO C  standard.  Any  conflict between the requirements described here
       and the ISO C standard is unintentional. This  volume  of  POSIX.1-2008
       defers to the ISO C standard.
       These functions shall convert the initial portion of the string pointed
       to by str to a type long and long  long  representation,  respectively.
       First, they decompose the input string into three parts:
        1. An  initial, possibly empty, sequence of white-space characters (as
           specified by isspace())
        2. A subject sequence interpreted as an integer  represented  in  some
           radix determined by the value of base
        3. A  final  string  of one or more unrecognized characters, including
           the terminating NUL character of the input string.
       Then they shall attempt to convert the subject sequence to an  integer,
       and return the result.
       If the value of base is 0, the expected form of the subject sequence is
       that of a decimal constant, octal constant,  or  hexadecimal  constant,
       any  of  which may be preceded by a '+' or '-' sign. A decimal constant
       begins with a non-zero digit, and consists of  a  sequence  of  decimal
       digits.  An  octal  constant consists of the prefix '0' optionally fol-
       lowed by a sequence of the digits '0' to '7' only. A  hexadecimal  con-
       stant  consists  of  the  prefix 0x or 0X followed by a sequence of the
       decimal digits and letters 'a' (or 'A') to 'f' (or 'F') with values  10
       to 15 respectively.
       If the value of base is between 2 and 36, the expected form of the sub-
       ject sequence is a sequence of letters and digits representing an inte-
       ger  with  the radix specified by base, optionally preceded by a '+' or
       '-' sign. The letters from 'a' (or 'A') to 'z' (or 'Z')  inclusive  are
       ascribed  the  values  10 to 35; only letters whose ascribed values are
       less than that of base are permitted. If the value of base is  16,  the
       characters  0x or 0X may optionally precede the sequence of letters and
       digits, following the sign if present.
       The subject sequence is defined as the longest initial  subsequence  of
       the  input  string,  starting  with the first non-white-space character
       that is of the expected form. The subject  sequence  shall  contain  no
       characters  if the input string is empty or consists entirely of white-
       space characters, or if the first non-white-space  character  is  other
       than a sign or a permissible letter or digit.
       If  the subject sequence has the expected form and the value of base is
       0, the sequence of characters starting with the first  digit  shall  be
       interpreted  as  an  integer  constant. If the subject sequence has the
       expected form and the value of base is between 2 and 36,  it  shall  be
       used  as the base for conversion, ascribing to each letter its value as
       given above. If the subject sequence  begins  with  a  minus-sign,  the
       value  resulting from the conversion shall be negated. A pointer to the
       final string shall be stored in the object pointed to by  endptr,  pro-
       vided that endptr is not a null pointer.
       In other than the C or POSIX locales, other implementation-defined sub-
       ject sequences may be accepted.
       If the subject sequence is empty or does not have the expected form, no
       conversion is performed; the value of str shall be stored in the object
       pointed to by endptr, provided that endptr is not a null pointer.
       These functions shall not change the setting of errno if successful.
       Since 0, {LONG_MIN} or {LLONG_MIN}, and {LONG_MAX} or  {LLONG_MAX}  are
       returned on error and are also valid returns on success, an application
       wishing to check for error situations should set errno to 0, then  call
       strtol() or strtoll(), then check errno.
RETURN VALUE
       Upon  successful completion, these functions shall return the converted
       value, if any. If no conversion could be performed, 0 shall be returned
       and errno may be set to [EINVAL].
       If  the  value  of base is not supported, 0 shall be returned and errno
       shall be set to [EINVAL].
       If the correct value is outside  the  range  of  representable  values,
       {LONG_MIN},  {LONG_MAX},  {LLONG_MIN}, or {LLONG_MAX} shall be returned
       (according to the sign of the value), and errno set to [ERANGE].
ERRORS
       These functions shall fail if:
       EINVAL The value of base is not supported.
       ERANGE The value to be returned is not representable.
       These functions may fail if:
       EINVAL No conversion could be performed.
       The following sections are informative.
EXAMPLES
       None.
APPLICATION USAGE
       Since the value of *endptr is unspecified if the value of base  is  not
       supported,  applications should either ensure that base has a supported
       value (0 or between 2 and 36) before the call, or check for an [EINVAL]
       error before examining *endptr.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       fscanf(), isalpha(), strtod()
       The Base Definitions volume of POSIX.1-2008, <stdlib.h>
COPYRIGHT
       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri-
       cal  and  Electronics  Engineers,  Inc  and  The  Open Group.  (This is
       POSIX.1-2008 with the 2013 Technical Corrigendum  1  applied.)  In  the
       event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group  Standard
       is  the  referee document. The original Standard can be obtained online
       at http://www.unix.org/online.html .
       Any typographical or formatting errors that appear  in  this  page  are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors,  see  https://www.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                           STRTOL(3P)