.\" Copyright (c) 1990, 1991 The Regents of the University of California. .\" All rights reserved. .\" .\" This code is derived from software contributed to Berkeley by .\" Chris Torek. .\" %sccs.include.redist.man% .\" .\" @(#)strtol.3 5.2 (Berkeley) %G% .\" .Dd .Dt STRTOL 3 .Os .Sh NAME .Nm strtol .Nd convert string value to a long integer .Sh SYNOPSIS .Fd #include .Fd #include .Ft long .Fn strtol "char *nptr" "char **endptr" "int base" .Sh DESCRIPTION The .Fn strtol function converts the string in .Fa nptr to a .Em long value according to the given .Fa base , which must be between 2 and 36 inclusive, or be the special value 0. .Pp The string may begin with an arbitrary amount of white space (as determined by .Xr isspace 3 ) followed by a single optional .Ql + or .Ql - sign. If .Fa base is zero or 16, the string may then include a .Ql 0x prefix, and the number will be read in base 16; otherwise, a zero .Fa base is taken as 10 (decimal) unless the next character is .Ql 0 , in which case it is taken as 8 (octal). .Pp The remainder of the string is converted to a .Em long 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 .Ql A in either upper or lower case represents 10, .Ql B represents 11, and so forth, with .Ql Z representing 35.) .Pp If .Fa endptr is non nil, .Fn strtol stores the address of the first invalid character in .Fa *endptr . If there were no digits at all, however, .Fn strtol stores the original value of .Fa nptr in .Fa *endptr . (Thus, if .Fa *nptr is not .Ql \e0 but .Fa **endptr is .Ql \e0 on return, the entire string was valid.) .Sh RETURN VALUES The .Fn strtol function returns the result of the conversion, unless the value would underflow or overflow. If an underflow occurs, .Fn strtol returns .Dv LONG_MIN . If an overflow occurs, .Fn strtol returns .Dv LONG_MAX . In both cases, .Va errno is set to .Er ERANGE . .Sh ERRORS .Bl -tag -width [ERANGE] .It Bq Er ERANGE The given string was out of range; the value converted has been clamped. .El .Sh SEE ALSO .Xr atof 3 , .Xr atoi 3 , .Xr atol 3 , .Xr strtod 3 , .Xr strtoul 3 .Sh STANDARDS The .Fn strtol function conforms to .St -ansiC . .Sh BUGS Ignores the current locale.