atol3
Convert a string to an integer
Part of atoi(3).
Usage
#include <stdlib.h>
int atoi(const char *nptr); long atol(const char *nptr); long long atoll(const char *nptr);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
atoll():
_ISOC99_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
Library
Standard C library (libc, -lc)
Overview
The atoi() function converts the initial portion of the string pointed to by nptr to int. The behavior is the same as
strtol(nptr, NULL, 10);
except that atoi() does not detect errors.
The atol() and atoll() functions behave the same as atoi(), except that they convert the initial portion of the string to their return type of long or long long.
Return value
The converted value or 0 on error.
Attributes
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
| atoi(), atol(), atoll() | Thread safety | MT-Safe locale |
Versions
POSIX.1 leaves the return value of atoi() on error unspecified. On glibc, musl libc, and uClibc, 0 is returned on error.
Releases
19 releases since Debian 1.1 (Buzz); the text changed 13 times.