strtol(3C)strtol(3C)NAME
strtol, strtoul, atol, atoi, strtoll, strtoull, atoll - convert string to
integer
SYNOPSIS
#include <stdlib.h>
long strtol (const char *str, char **ptr, int base);
unsigned long strtoul (const char *str, char **ptr, int base);
long long strtoll (const char *str, char **ptr, int base);
unsigned long long strtoull (const char *str, char **ptr, int base);
int atoi (const char *str);
long atol (const char *str);
long long atoll (const char *str);
DESCRIPTION
strtol returns as a long integer the value represented by the character
string pointed to by str. The string is scanned up to the first
character inconsistent with the base. Leading ``white-space'' characters
[as defined by isspace in ctype(3C)] are ignored.
If the value of ptr is not (char **)NULL, a pointer to the character
terminating the scan is returned in the location pointed to by ptr. If
no integer can be formed, that location is set to str, and zero is
returned.
If base is between 2 and 36, inclusive, it is used as the base for
conversion. After an optional leading sign, leading zeros are ignored,
and ``0x'' or ``0X'' is ignored if base is 16.
If base is zero, the string itself determines the base as follows: After
an optional leading sign a leading zero indicates octal conversion, and a
leading ``0x'' or ``0X'' hexadecimal conversion. Otherwise, decimal
conversion is used.
Truncation from long to int can, of course, take place upon assignment or
by an explicit cast.
If the value represented by str would cause overflow, LONG_MAX or
LONG_MIN is returned (according to the sign of the value), and errno is
set to the value, ERANGE.
strtoul is similar to strtol except that strtoul returns as an unsigned
long integer the value represented by str. If the value represented by
str would cause overflow, ULONG_MAX is returned, and errno is set to the
value, ERANGE.
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strtol(3C)strtol(3C)
strtoll is similar to strtol except that strtoll returns as a long long
integer the value represented by str. If the value represented by str
would cause overflow, LONGLONG_MAX or LONGLONG_MIN is returned (according
to the sign of the value), and errno is set to the value, ERANGE.
strtoull is similar to strtoll except that strtoull returns as an
unsigned long long integer the value represented by str. If the value
represented by str would cause overflow, ULONGLONG_MAX is returned, and
errno is set to the value, ERANGE.
Except for behavior on error, atol(str) is equivalent to:
strtol(str, (char **)NULL, 10)
Except for behavior on error, atoi(str) is equivalent to:
(int) strtol(str, (char **)NULL, 10)
Except for behavior on error, atoll(str) is equivalent to:
strtoll(str, (char **)NULL, 10)
DIAGNOSTICS
If strtol is given a base greater than 36 or less than 2, it returns 0
and sets errno to EINVAL.
SEE ALSOctype(3C), strtod(3C), scanf(3S).
NOTES
strtol no longer accepts values greater than LONG_MAX as valid input.
Use strtoul instead.
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