atol3p
Convert a string to a long integer
Usage
#include <stdlib.h>
long atol(const char *nptr); long long atoll(const char *nptr);
Prolog
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
Overview
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.1‐2017 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.
The following sections are informative.
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.