.\" Copyright (c) 1990, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" This code is derived from software contributed to Berkeley by .\" Chris Torek and the American National Standards Committee X3, .\" on Information Processing Systems. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)strtol.3 8.1 (Berkeley) 6/4/93 .\" $FreeBSD: src/lib/libc/stdlib/strtol.3,v 1.20 2005/01/22 18:02:58 ache Exp $ .\" .Dd November 28, 2001 .Dt STRTOL 3 .Os .Sh NAME .Nm strtoimax , .Nm strtol , .Nm strtoll , .Nm strtoq .Nd "convert a string value to a" .Vt long , "long long" , intmax_t or .Vt quad_t integer .Sh LIBRARY .Lb libc .Sh SYNOPSIS .In inttypes.h .Ft intmax_t .Fo strtoimax .Fa "const char *restrict str" .Fa "char **restrict endptr" .Fa "int base" .Fc .In stdlib.h .Ft long .Fo strtol .Fa "const char *restrict str" .Fa "char **restrict endptr" .Fa "int base" .Fc .Ft long long .Fo strtoll .Fa "const char *restrict str" .Fa "char **restrict endptr" .Fa "int base" .Fc .In sys/types.h .In stdlib.h .In limits.h .Ft quad_t .Fo strtoq .Fa "const char *str" .Fa "char **endptr" .Fa "int base" .Fc .Sh DESCRIPTION The .Fn strtol function converts the string in .Fa str to a .Vt long value. The .Fn strtoll function converts the string in .Fa str to a .Vt "long long" value. The .Fn strtoimax function converts the string in .Fa str to an .Vt intmax_t value. The .Fn strtoq function converts the string in .Fa str to a .Vt quad_t value. The conversion is done 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 .Dq Li 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 .Vt long , "long long" , intmax_t or .Vt quad_t 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 not .Dv NULL , .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 str in .Fa *endptr . (Thus, if .Fa *str is not .Ql \e0 but .Fa **endptr is .Ql \e0 on return, the entire string was valid.) .Pp Extended locale versions of these functions are documented in .Xr strtol_l 3 . See .Xr xlocale 3 for more information. .Sh RETURN VALUES The .Fn strtol , .Fn strtoll , .Fn strtoimax , and .Fn strtoq functions return the result of the conversion, unless the value would underflow or overflow. If no conversion could be performed, 0 is returned and the global variable .Va errno is set to .Er EINVAL (the last feature is not portable across all platforms). If an overflow or underflow occurs, .Va errno is set to .Er ERANGE and the function return value is clamped according to the following table. .Bl -column -offset indent ".Fn strtoimax" ".Dv INTMAX_MIN" ".Dv INTMAX_MAX" .It Sy Function Ta Sy underflow Ta Sy overflow .It Fn strtol Ta Dv LONG_MIN Ta Dv LONG_MAX .It Fn strtoll Ta Dv LLONG_MIN Ta Dv LLONG_MAX .It Fn strtoimax Ta Dv INTMAX_MIN Ta Dv INTMAX_MAX .It Fn strtoq Ta Dv LLONG_MIN Ta Dv LLONG_MAX .El .Sh ERRORS .Bl -tag -width Er .It Bq Er EINVAL The value of .Fa base is not supported or no conversion could be performed (the last feature is not portable across all platforms). .It Bq Er ERANGE The given string was out of range; the value converted has been clamped. .El .Sh LEGACY SYNOPSIS .Fd #include <stdlib.h> .Fd #include <limits.h> .Pp .In limits.h is necessary for the .Fn strtol and .Fn strtoll functions. .Sh SEE ALSO .Xr atof 3 , .Xr atoi 3 , .Xr atol 3 , .Xr strtod 3 , .Xr strtol_l 3 , .Xr strtoul 3 , .Xr wcstol 3 , .Xr compat 5 .Sh STANDARDS The .Fn strtol function conforms to .St -isoC . The .Fn strtoll and .Fn strtoimax functions conform to .St -isoC-99 . The .Bx .Fn strtoq function is deprecated.