1. Tech

Your suggestion is on its way!

An email with a link to:


was emailed to:

Thanks for sharing About.com with others!

Linux / Unix Command: strtoq
Command Library


strtol, strtoll, strtoq - convert a string to a long integer.  


#include <stdlib.h>

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

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


The strtol() function converts the initial part of 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.

The strtoll() function works just like the strtol() function but returns a long long integer 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. Precisely the same holds for strtoll() (with LLONG_MIN and LLONG_MAX instead of LONG_MIN and LONG_MAX).  


The resulting value was out of range.
(not in C99) The given base contains an unsupported value.

The implementation may also set errno to EINVAL in case no conversion was performed (no digits seen, and 0 returned).  


atof(3), atoi(3), atol(3), strtod(3), strtoul(3)

Important: Use the man command (% man) to see how a command is used on your particular computer.

>> Linux/Unix Command Library

>> Shell Command Library

  1. About.com
  2. Tech
  3. Linux

©2015 About.com. All rights reserved.