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atoll, _atoll_l, _wtoll, _wtoll_l

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Converts a string to a long long integer.

Syntax

long long atoll(
   const char *str
);
long long _wtoll(
   const wchar_t *str
);
long long _atoll_l(
   const char *str,
   _locale_t locale
);
long long _wtoll_l(
   const wchar_t *str,
   _locale_t locale
);

Parameters

str
String to be converted.

locale
Locale to use.

Return value

Each function returns the long long value that's produced by interpreting the input characters as a number. The return value for atoll is 0 if the input can't be converted to a value of that type.

For overflow with large positive integral values, atoll returns LLONG_MAX, and for overflow with large negative integral values, it returns LLONG_MIN.

In all out-of-range cases, errno is set to ERANGE. If the parameter that's passed in is NULL, the invalid parameter handler is invoked, as described in Parameter validation. If execution is allowed to continue, these functions set errno to EINVAL and return 0.

Remarks

These functions convert a character string to a long long integer value.

The input string is a sequence of characters that can be interpreted as a numerical value of the specified type. The function stops reading the input string at the first character that it can't recognize as part of a number. This character might be the null character ('\0' or L'\0') that terminates the string.

The str argument to atoll has the following form:

[whitespace] [sign] [digits]

A whitespace consists of space or tab characters, which are ignored; sign is either plus (+) or minus (-); and digits are one or more digits.

_wtoll is identical to atoll except that it takes a wide character string as a parameter.

The versions of these functions that have the _l suffix are identical to the versions that don't have it, except that they use the locale parameter that's passed in instead of the current locale. For more information, see Locale.

By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.

Generic-text routine mappings

Tchar.h routine _UNICODE and _MBCS not defined _MBCS defined _UNICODE defined
_tstoll atoll atoll _wtoll
_tstoll_l _atoll_l _atoll_l _wtoll_l
_ttoll _atoll _atoll _wtoll

Requirements

Routines Required header
atoll, _atoll_l <stdlib.h>
_wtoll, _wtoll_l <stdlib.h> or <wchar.h>

Example

This program shows how to use the atoll functions to convert numbers stored as strings to numeric values.

// crt_atoll.c
// Build with: cl /W4 /Tc crt_atoll.c
// This program shows how to use the atoll
// functions to convert numbers stored as
// strings to numeric values.
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>

int main(void)
{
    char *str = NULL;
    long long value = 0;

    // An example of the atoll function
    // with leading and trailing white spaces.
    str = "  -27182818284 ";
    value = atoll(str);
    printf("Function: atoll(\"%s\") = %lld\n", str, value);

    // Another example of the atoll function
    // with an arbitrary decimal point.
    str = "314127.64";
    value = atoll(str);
    printf("Function: atoll(\"%s\") = %lld\n", str, value);

    // Another example of the atoll function
    // with an overflow condition occurring.
    str = "3336402735171707160320";
    value = atoll(str);
    printf("Function: atoll(\"%s\") = %lld\n", str, value);
    if (errno == ERANGE)
    {
       printf("Overflow condition occurred.\n");
    }
}

Function: atoll("  -27182818284 ") = -27182818284
Function: atoll("314127.64") = 314127
Function: atoll("3336402735171707160320") = 9223372036854775807
Overflow condition occurred.

See also

Data conversion
Math and floating-point support
Locale
_ecvt
_fcvt
_gcvt
setlocale, _wsetlocale
_atodbl, _atodbl_l, _atoldbl, _atoldbl_l, _atoflt, _atoflt_l