NAME

atol, atoll — convert a string to a long integer

SYNOPSIS

#include <stdlib.h>

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


DESCRIPTION

^[CX] 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.1-2024 defers to the ISO C standard.

Except as noted below, the call atol(nptr) shall be equivalent to:

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

Except as noted below, the call to atoll(nptr) shall be equivalent to:

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

The handling of errors may differ. If the value cannot be represented, the behavior is undefined.

RETURN VALUE

These functions shall return the converted value if the value can be represented.

ERRORS

No errors are defined.

EXAMPLES

None.

APPLICATION USAGE

If the number is not known to be in range, strtol() or strtoll() should be used because atol() and atoll() are not required to perform any error checking.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

strtol

XBD <stdlib.h>

CHANGE HISTORY

First released in Issue 1. Derived from Issue 1 of the SVID.

Issue 6

The atoll() function is added for alignment with the ISO/IEC 9899:1999 standard.

Issue 7

SD5-XSH-ERN-61 is applied, correcting the DESCRIPTION of atoll().

POSIX.1-2008, Technical Corrigendum 2, XSH/TC2-2008/0046 [892] is applied.