.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) .\" .\" Permission is granted to make and distribute verbatim copies of this .\" manual provided the copyright notice and this permission notice are .\" preserved on all copies. .\" .\" Permission is granted to copy and distribute modified versions of this .\" manual under the conditions for verbatim copying, provided that the .\" entire resulting derived work is distributed under the terms of a .\" permission notice identical to this one .\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume no .\" responsibility for errors or omissions, or for damages resulting from .\" the use of the information contained herein. The author(s) may not .\" have taken the same level of care in the production of this manual, .\" which is licensed free of charge, as they might when working .\" professionally. .\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" .\" References consulted: .\" Linux libc source code .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) .\" 386BSD man pages .\" Modified Sun Jul 25 10:53:39 1993 by Rik Faith (faith@cs.unc.edu) .\" Added correction due to nsd@bbc.com (Nick Duffek) - aeb, 950610 .TH STRTOL 3 "10 June 1995" "GNU" "Linux Programmer's Manual" .SH NAME strtol \- convert a string to a long integer. .SH SYNOPSIS .nf .B #include .sp .BI "long int strtol(const char *" nptr ", char **" endptr ", int " base ); .fi .SH DESCRIPTION The \fBstrtol()\fP function converts the string in \fInptr\fP to a long integer value according to the given \fIbase\fP, which must be between 2 and 36 inclusive, or be the special value 0. .PP The string must begin with an arbitrary amount of white space (as determined by .BR isspace (3)) followed by a single optional `+' or `-' sign. If \fIbase\fP is zero or 16, the string may then include a `0x' prefix, and the number will be read in base 16; otherwise, a zero \fIbase\fP is taken as 10 (decimal) unless the next character is `0', in which case it is taken as 8 (octal). .PP 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.) .PP If \fIendptr\fP is not NULL, \fBstrtol()\fP stores the address of the first invalid character in \fI*endptr\fP. If there were no digits at all, \fBstrtol()\fP stores the original value of \fInptr\fP in \fI*endptr\fP. (Thus, if \fI*nptr\fP is not `\\0' but \fI**endptr\fP is `\\0' on return, the entire string is valid.) .SH "RETURN VALUE" The \fBstrtol()\fP function returns the result of the conversion, unless the value would underflow or overflow. If an underflow occurs, \fBstrtol()\fP returns LONG_MIN. If an overflow occurs, \fBstrtol()\fP returns LONG_MAX. In both cases, \fIerrno\fP is set to ERANGE. .SH "ERRORS" .TP .B ERANGE The given string was out of range; the value converted has been clamped. .SH "CONFORMING TO" SVID 3, BSD 4.3, ISO 9899 .SH "SEE ALSO" .BR atof "(3), " atoi "(3), " atol "(3), " strtod "(3), " strtoul (3) .SH BUGS Ignores the current locale.