Man Pages

---

Back to Software Index  Manpage Top Level

Name

Synopsis

#include <stdlib.h>

long strtol(const char *str, char **ptr, int base);

long long strtoll(const char *str, char **ptr, int base);

unsigned long strtoul(const char *str, char **ptr, int base);

unsigned long long strtoull(const char *str, char **ptr, int base);

long atol(const char *str);

long long atoll(const char *str);

int atoi(const char *str);

char *lltostr(long long value, char *ptr);

char *ulltostr(unsigned long long value, char *ptr);

MT-Level

MT-Safe

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 base. Leading ‘‘white-space’’ characters (as defined by isspace() in ctype(3C) ) are ignored.

strtoll() is similar to strtol() except that the value is returned as a long long.

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 positive (and not greater than 36), 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() and strtoull() are similar to strtol() except that strtoul() returns the value represented by str as an unsigned long integer and strtoull() returns this value as an unsigned long long. If the value represented by str would cause overflow, ULONG_MAX is returned, and errno is set to the value, ERANGE .

Except for behavior on error, atol() is equivalent to: strtol(str, (char **)NULL, 10).

Except for behavior on error, atoll() is equivalent to: strtoll(str, (char **)NULL, 10).

Except for behavior on error, atoi() is equivalent to: (int) strtol(str, (char **)NULL, 10).

lltostr() returns a pointer to the string represented by the long long value.

ulltostr() is similar to lltostr() except that value is an unsigned long long.

Return Values

See Also

Notes

strtol() no longer accepts values greater than LONG_MAX as valid input. Use strtoul() instead.

Table of Contents

• Name
• Synopsis
• MT-Level
• Description
• Return Values
• See Also
• Notes