atol

Convert ASCII string to long or long long integer

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Contents

Interface
Description
Errors
See Also
Standards
Page Comments

Interface

#include <stdlib.h>
long  atol (const char *nptr)
long long  atoll (const char *nptr)

#include <xlocale.h>
long  atol_l (const char *nptr, locale_t loc)
long long  atoll_l (const char *nptr, locale_t loc)

Description

The atol function converts the initial portion of the string pointed to by nptr to long integer representation. It is equivalent to:

strtol(nptr, (char **)NULL, 10);

The atoll function converts the initial portion of the string pointed to by nptr to long long integer representation. It is equivalent to:

strtoll(nptr, (char **)NULL, 10);

While the atol and atoll functions use the current locale, the atol_l and atoll_l functions may be passed locales directly.

Example 1

#include <stdio.h>
#include <stdlib.h>
 
int main()
{
  char x[20] = "2147111222";
  long max = atol(x);
  printf("max = %ld\n", max);
  return 0;
}

Output:

max = 2147111222

Errors

The functions atol and atoll need not affect the value of errno on an error.

Standards

The atol function conforms to ISO/IEC 9899:1990 ("ISO C90"). The atoll function conforms to ISO/IEC 9899:1999 ("ISO C99").

Page Comments

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long	`atol` (const char *nptr)
long long	`atoll` (const char *nptr)

long	`atol_l` (const char *nptr, locale_t loc)
long long	`atoll_l` (const char *nptr, locale_t loc)