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Diffstat (limited to 'src/lib/libc/stdlib/strtod.3')
| -rw-r--r-- | src/lib/libc/stdlib/strtod.3 | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/src/lib/libc/stdlib/strtod.3 b/src/lib/libc/stdlib/strtod.3 new file mode 100644 index 0000000000..0066cc02f3 --- /dev/null +++ b/src/lib/libc/stdlib/strtod.3 | |||
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| 1 | .\" Copyright (c) 1990, 1991 The Regents of the University of California. | ||
| 2 | .\" All rights reserved. | ||
| 3 | .\" | ||
| 4 | .\" This code is derived from software contributed to Berkeley by | ||
| 5 | .\" the American National Standards Committee X3, on Information | ||
| 6 | .\" 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 | .\" $OpenBSD: strtod.3,v 1.16 2012/09/16 17:54:03 jmc Exp $ | ||
| 33 | .\" | ||
| 34 | .Dd $Mdocdate: September 16 2012 $ | ||
| 35 | .Dt STRTOD 3 | ||
| 36 | .Os | ||
| 37 | .Sh NAME | ||
| 38 | .Nm strtod , | ||
| 39 | .Nm strtof , | ||
| 40 | .Nm strtold | ||
| 41 | .Nd convert | ||
| 42 | .Tn ASCII | ||
| 43 | string to double, float or long double | ||
| 44 | .Sh SYNOPSIS | ||
| 45 | .Fd #include <math.h> | ||
| 46 | .Fd #include <stdlib.h> | ||
| 47 | .Ft double | ||
| 48 | .Fn strtod "const char *nptr" "char **endptr" | ||
| 49 | .Pp | ||
| 50 | .Ft float | ||
| 51 | .Fn strtof "const char *nptr" "char **endptr" | ||
| 52 | .Pp | ||
| 53 | .Ft long double | ||
| 54 | .Fn strtold "const char *nptr" "char **endptr" | ||
| 55 | .Sh DESCRIPTION | ||
| 56 | The | ||
| 57 | .Fn strtod | ||
| 58 | function converts the initial portion of the string pointed to by | ||
| 59 | .Fa nptr | ||
| 60 | to | ||
| 61 | .Li double | ||
| 62 | representation. | ||
| 63 | The | ||
| 64 | .Fn strtof | ||
| 65 | function converts the initial portion of the string pointed to by | ||
| 66 | .Fa nptr | ||
| 67 | to | ||
| 68 | .Li float | ||
| 69 | representation. | ||
| 70 | The | ||
| 71 | .Fn strtold | ||
| 72 | function converts the initial portion of the string pointed to by | ||
| 73 | .Fa nptr | ||
| 74 | to | ||
| 75 | .Li long double | ||
| 76 | representation. | ||
| 77 | .Pp | ||
| 78 | The expected form of the string is an optional plus | ||
| 79 | .Pq Ql + | ||
| 80 | or minus sign | ||
| 81 | .Pq Ql - | ||
| 82 | followed by a sequence of digits optionally containing | ||
| 83 | a decimal-point character, optionally followed by an exponent. | ||
| 84 | An exponent consists of an | ||
| 85 | .Sq E | ||
| 86 | or | ||
| 87 | .Sq e , | ||
| 88 | followed by an optional plus or minus sign, followed by a sequence of digits. | ||
| 89 | .Pp | ||
| 90 | Alternatively, if the portion of the string following the optional | ||
| 91 | plus or minus sign begins with | ||
| 92 | .Dq INF | ||
| 93 | or | ||
| 94 | .Dq NAN , | ||
| 95 | ignoring case, it is interpreted as an infinity or a quiet \*(Na, | ||
| 96 | respectively. | ||
| 97 | The syntax | ||
| 98 | .Dq NAN Ns Pq Ar s , | ||
| 99 | where | ||
| 100 | .Ar s | ||
| 101 | is an alphanumeric string, produces the same value as the call | ||
| 102 | .Fo nan | ||
| 103 | .Qq Ar s Ns | ||
| 104 | .Fc | ||
| 105 | (respectively, | ||
| 106 | .Fo nanf | ||
| 107 | .Qq Ar s Ns | ||
| 108 | .Fc | ||
| 109 | and | ||
| 110 | .Fo nanl | ||
| 111 | .Qq Ar s Ns | ||
| 112 | .Fc . ) | ||
| 113 | .Pp | ||
| 114 | In any of the above cases, leading whitespace characters in the | ||
| 115 | string (as defined by the | ||
| 116 | .Xr isspace 3 | ||
| 117 | function) are skipped. | ||
| 118 | .Sh RETURN VALUES | ||
| 119 | The | ||
| 120 | .Fn strtod , | ||
| 121 | .Fn strtof | ||
| 122 | and | ||
| 123 | .Fn strtold | ||
| 124 | functions return the converted value, if any. | ||
| 125 | .Pp | ||
| 126 | If | ||
| 127 | .Fa endptr | ||
| 128 | is not | ||
| 129 | .Dv NULL , | ||
| 130 | a pointer to the character after the last character used | ||
| 131 | in the conversion is stored in the location referenced by | ||
| 132 | .Fa endptr . | ||
| 133 | .Pp | ||
| 134 | If no conversion is performed, zero is returned and the value of | ||
| 135 | .Fa nptr | ||
| 136 | is stored in the location referenced by | ||
| 137 | .Fa endptr . | ||
| 138 | .Pp | ||
| 139 | If the correct value would cause overflow, plus or minus | ||
| 140 | .Dv HUGE_VAL | ||
| 141 | is returned (according to the sign of the value), and | ||
| 142 | .Er ERANGE | ||
| 143 | is stored in | ||
| 144 | .Va errno . | ||
| 145 | If the correct value would cause underflow, zero is returned and | ||
| 146 | .Er ERANGE | ||
| 147 | is stored in | ||
| 148 | .Va errno . | ||
| 149 | .Sh ERRORS | ||
| 150 | .Bl -tag -width Er | ||
| 151 | .It Bq Er ERANGE | ||
| 152 | Overflow or underflow occurred. | ||
| 153 | .El | ||
| 154 | .Sh SEE ALSO | ||
| 155 | .Xr atof 3 , | ||
| 156 | .Xr atoi 3 , | ||
| 157 | .Xr atol 3 , | ||
| 158 | .Xr strtol 3 , | ||
| 159 | .Xr strtoul 3 | ||
| 160 | .Sh STANDARDS | ||
| 161 | The | ||
| 162 | .Fn strtod | ||
| 163 | function conforms to | ||
| 164 | .St -ansiC-89 . | ||
| 165 | The | ||
| 166 | .Fn strtof | ||
| 167 | and | ||
| 168 | .Fn strtold | ||
| 169 | functions conform to | ||
| 170 | .St -ansiC-99 . | ||
