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.\" @(#)strtol.3 8.1 (Berkeley) 6/4/93 33.\" 34.Dd August 21, 2023 35.Dt STRTOL 3 36.Os 37.Sh NAME 38.Nm strtol , strtoll , strtoimax , strtoq 39.Nd "convert a string value to a" 40.Vt long , "long long" , intmax_t 41or 42.Vt quad_t 43integer 44.Sh LIBRARY 45.Lb libc 46.Sh SYNOPSIS 47.In stdlib.h 48.In limits.h 49.Ft long 50.Fn strtol "const char * restrict nptr" "char ** restrict endptr" "int base" 51.Ft long long 52.Fn strtoll "const char * restrict nptr" "char ** restrict endptr" "int base" 53.In inttypes.h 54.Ft intmax_t 55.Fn strtoimax "const char * restrict nptr" "char ** restrict endptr" "int base" 56.In sys/types.h 57.In stdlib.h 58.In limits.h 59.Ft quad_t 60.Fn strtoq "const char *nptr" "char **endptr" "int base" 61.Sh DESCRIPTION 62The 63.Fn strtol 64function 65converts the string in 66.Fa nptr 67to a 68.Vt long 69value. 70The 71.Fn strtoll 72function 73converts the string in 74.Fa nptr 75to a 76.Vt "long long" 77value. 78The 79.Fn strtoimax 80function 81converts the string in 82.Fa nptr 83to an 84.Vt intmax_t 85value. 86The 87.Fn strtoq 88function 89converts the string in 90.Fa nptr 91to a 92.Vt quad_t 93value. 94The conversion is done according to the given 95.Fa base , 96which must be between 2 and 36 inclusive, 97or be the special value 0. 98.Pp 99The string may begin with an arbitrary amount of white space 100(as determined by 101.Xr isspace 3 ) 102followed by a single optional 103.Ql + 104or 105.Ql - 106sign. 107If 108.Fa base 109is zero or 16, 110the string may then include a 111.Dq Li 0b 112prefix, and the number will be read in base 2; or it may include a 113.Dq Li 0x 114prefix, 115and the number will be read in base 16; otherwise, a zero 116.Fa base 117is taken as 10 (decimal) unless the next character is 118.Ql 0 , 119in which case it is taken as 8 (octal). 120.Pp 121The remainder of the string is converted to a 122.Vt long , "long long" , intmax_t 123or 124.Vt quad_t 125value in the obvious manner, 126stopping at the first character which is not a valid digit 127in the given base. 128(In bases above 10, the letter 129.Ql A 130in either upper or lower case 131represents 10, 132.Ql B 133represents 11, and so forth, with 134.Ql Z 135representing 35.) 136.Pp 137If 138.Fa endptr 139is not 140.Dv NULL , 141.Fn strtol 142stores the address of the first invalid character in 143.Fa *endptr . 144If there were no digits at all, however, 145.Fn strtol 146stores the original value of 147.Fa nptr 148in 149.Fa *endptr . 150(Thus, if 151.Fa *nptr 152is not 153.Ql \e0 154but 155.Fa **endptr 156is 157.Ql \e0 158on return, the entire string was valid.) 159.Sh RETURN VALUES 160The 161.Fn strtol , 162.Fn strtoll , 163.Fn strtoimax 164and 165.Fn strtoq 166functions 167return the result of the conversion, 168unless the value would underflow or overflow. 169If no conversion could be performed, 0 is returned and 170the global variable 171.Va errno 172is set to 173.Er EINVAL 174(the last feature is not portable across all platforms). 175If an overflow or underflow occurs, 176.Va errno 177is set to 178.Er ERANGE 179and the function return value is clamped according 180to the following table. 181.Bl -column -offset indent ".Fn strtoimax" ".Sy underflow" ".Sy overflow" 182.It Sy Function Ta Sy underflow Ta Sy overflow 183.It Fn strtol Ta Dv LONG_MIN Ta Dv LONG_MAX 184.It Fn strtoll Ta Dv LLONG_MIN Ta Dv LLONG_MAX 185.It Fn strtoimax Ta Dv INTMAX_MIN Ta Dv INTMAX_MAX 186.It Fn strtoq Ta Dv LLONG_MIN Ta Dv LLONG_MAX 187.El 188.Sh ERRORS 189.Bl -tag -width Er 190.It Bq Er EINVAL 191The value of 192.Fa base 193is not supported or 194no conversion could be performed 195(the last feature is not portable across all platforms). 196.It Bq Er ERANGE 197The given string was out of range; the value converted has been clamped. 198.El 199.Sh SEE ALSO 200.Xr atof 3 , 201.Xr atoi 3 , 202.Xr atol 3 , 203.Xr strtod 3 , 204.Xr strtonum 3 , 205.Xr strtoul 3 , 206.Xr wcstol 3 207.Sh STANDARDS 208The 209.Fn strtol 210function 211conforms to 212.St -isoC . 213The 214.Fn strtoll 215and 216.Fn strtoimax 217functions 218conform to 219.St -isoC-99 . 220The 221.Bx 222.Fn strtoq 223function is deprecated. 224