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atoll, _atoll_l, _wtoll, _wtoll_l

Visual Studio 2013

Converts a string to a long long integer.

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
);

str

String to be converted.

locale

Locale to use.

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 cannot 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.

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 cannot 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.

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

Routines

Required header

atoll, _atoll_l

<stdlib.h>

_wtoll, _wtoll_l

<stdlib.h> or <wchar.h>

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.
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