STRTOL

Section: Linux Programmer's Manual (3 )
Updated: 1995-06-10
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NAME

strtol - convert a string to a long integer.

SYNOPSIS

#include <stdlib.h>

long int strtol(const char *nptr, char **endptr, int base);

DESCRIPTION

The strtol() function converts the string in nptr to a long integer value according to the given base, which must be between 2 and 36 inclusive, or be the special value 0.

The string must begin with an arbitrary amount of white space (as determined by isspace(3)) followed by a single optional `+' or `-' sign. If base is zero or 16, the string may then include a `0x' prefix, and the number will be read in base 16; otherwise, a zero base is taken as 10 (decimal) unless the next character is `0', in which case it is taken as 8 (octal).

The remainder of the string is converted to a long int value in the obvious manner, stopping at the first character which is not a valid digit in the given base. (In bases above 10, the letter `A' in either upper or lower case represents 10, `B' represents 11, and so forth, with `Z' representing 35.)

If endptr is not NULL, strtol() stores the address of the first invalid character in *endptr. If there were no digits at all, strtol() stores the original value of nptr in *endptr (and returns 0). In particular, if *nptr is not `\0' but **endptr is `\0' on return, the entire string is valid.

RETURN VALUE

The strtol() function returns the result of the conversion, unless the value would underflow or overflow. If an underflow occurs, strtol() returns LONG_MIN. If an overflow occurs, strtol() returns LONG_MAX. In both cases, errno is set to ERANGE.

ERRORS

ERANGE: The given string was out of range; the value converted has been clamped.

CONFORMING TO

SVID 3, BSD 4.3, ISO 9899

BUGS

Ignores the current locale.

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Time: 01:56:08 GMT, January 21, 2025