1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Chris Torek and the American National Standards Committee X3, 6.\" on Information Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.Dd August 21, 2023 33.Dt STRTOL 3 34.Os 35.Sh NAME 36.Nm strtol , strtoll , strtoimax , strtoq 37.Nd "convert a string value to a" 38.Vt long , "long long" , intmax_t 39or 40.Vt quad_t 41integer 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In stdlib.h 46.In limits.h 47.Ft long 48.Fn strtol "const char * restrict nptr" "char ** restrict endptr" "int base" 49.Ft long long 50.Fn strtoll "const char * restrict nptr" "char ** restrict endptr" "int base" 51.In inttypes.h 52.Ft intmax_t 53.Fn strtoimax "const char * restrict nptr" "char ** restrict endptr" "int base" 54.In sys/types.h 55.In stdlib.h 56.In limits.h 57.Ft quad_t 58.Fn strtoq "const char *nptr" "char **endptr" "int base" 59.Sh DESCRIPTION 60The 61.Fn strtol 62function 63converts the string in 64.Fa nptr 65to a 66.Vt long 67value. 68The 69.Fn strtoll 70function 71converts the string in 72.Fa nptr 73to a 74.Vt "long long" 75value. 76The 77.Fn strtoimax 78function 79converts the string in 80.Fa nptr 81to an 82.Vt intmax_t 83value. 84The 85.Fn strtoq 86function 87converts the string in 88.Fa nptr 89to a 90.Vt quad_t 91value. 92The conversion is done according to the given 93.Fa base , 94which must be between 2 and 36 inclusive, 95or be the special value 0. 96.Pp 97The string may begin with an arbitrary amount of white space 98(as determined by 99.Xr isspace 3 ) 100followed by a single optional 101.Ql + 102or 103.Ql - 104sign. 105If 106.Fa base 107is zero or 16, 108the string may then include a 109.Dq Li 0b 110prefix, and the number will be read in base 2; or it may include a 111.Dq Li 0x 112prefix, 113and the number will be read in base 16; otherwise, a zero 114.Fa base 115is taken as 10 (decimal) unless the next character is 116.Ql 0 , 117in which case it is taken as 8 (octal). 118.Pp 119The remainder of the string is converted to a 120.Vt long , "long long" , intmax_t 121or 122.Vt quad_t 123value in the obvious manner, 124stopping at the first character which is not a valid digit 125in the given base. 126(In bases above 10, the letter 127.Ql A 128in either upper or lower case 129represents 10, 130.Ql B 131represents 11, and so forth, with 132.Ql Z 133representing 35.) 134.Pp 135If 136.Fa endptr 137is not 138.Dv NULL , 139.Fn strtol 140stores the address of the first invalid character in 141.Fa *endptr . 142If there were no digits at all, however, 143.Fn strtol 144stores the original value of 145.Fa nptr 146in 147.Fa *endptr . 148(Thus, if 149.Fa *nptr 150is not 151.Ql \e0 152but 153.Fa **endptr 154is 155.Ql \e0 156on return, the entire string was valid.) 157.Sh RETURN VALUES 158The 159.Fn strtol , 160.Fn strtoll , 161.Fn strtoimax 162and 163.Fn strtoq 164functions 165return the result of the conversion, 166unless the value would underflow or overflow. 167If no conversion could be performed, 0 is returned and 168the global variable 169.Va errno 170is set to 171.Er EINVAL 172(the last feature is not portable across all platforms). 173If an overflow or underflow occurs, 174.Va errno 175is set to 176.Er ERANGE 177and the function return value is clamped according 178to the following table. 179.Bl -column -offset indent ".Fn strtoimax" ".Sy underflow" ".Sy overflow" 180.It Sy Function Ta Sy underflow Ta Sy overflow 181.It Fn strtol Ta Dv LONG_MIN Ta Dv LONG_MAX 182.It Fn strtoll Ta Dv LLONG_MIN Ta Dv LLONG_MAX 183.It Fn strtoimax Ta Dv INTMAX_MIN Ta Dv INTMAX_MAX 184.It Fn strtoq Ta Dv LLONG_MIN Ta Dv LLONG_MAX 185.El 186.Sh ERRORS 187.Bl -tag -width Er 188.It Bq Er EINVAL 189The value of 190.Fa base 191is not supported or 192no conversion could be performed 193(the last feature is not portable across all platforms). 194.It Bq Er ERANGE 195The given string was out of range; the value converted has been clamped. 196.El 197.Sh SEE ALSO 198.Xr atof 3 , 199.Xr atoi 3 , 200.Xr atol 3 , 201.Xr strtod 3 , 202.Xr strtonum 3 , 203.Xr strtoul 3 , 204.Xr wcstol 3 205.Sh STANDARDS 206The 207.Fn strtol 208function 209conforms to 210.St -isoC . 211The 212.Fn strtoll 213and 214.Fn strtoimax 215functions 216conform to 217.St -isoC-99 . 218The 219.Bx 220.Fn strtoq 221function is deprecated. 222