ATOL(3) Library Functions Manual ATOL(3)

atol atoll — convert a string to a long integer

#include <stdlib.h>

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

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 IEEE Std 1003.1-2001 (“POSIX.1”) defers to the ISO C standard.

The call atol ( str) shall be equivalent to:

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

The call atoll ( str) shall be equivalent to:

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

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

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

No errors are defined.

None.

The atol () function is subsumed by strtol(3) but is retained because it is used extensively in existing code. If the number is not known to be in range, strtol(3) should be used because atol () is not required to perform any error checking.

None.

None.

strtol(3), the Base Definitions volume of IEEE Std 1003.1-2001 (“POSIX.1”), <stdlib.h>

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

The atoll () function is added for alignment with the ISO/IEC 9899:1999 (“ISO C99”) standard.

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January 1, 2004 posix.fail