projects / unix-history / blame
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1 | .\" Copyright (c) 1990 The Regents of the University of California. |
| 2 | .\" All rights reserved. | |
| f11907db | 3 | .\" |
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4 | .\" %sccs.include.redist.man% |
| 5 | .\" | |
| 6 | .\" @(#)atof.3 6.2 (Berkeley) %G% | |
| 7 | .\" | |
| 8 | .TH ATOF 3 "" | |
| 9 | .UC 7 | |
| f11907db | 10 | .SH NAME |
| 44e6327a | 11 | atof \- convert ASCII string to double |
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12 | .SH SYNOPSIS |
| 13 | .nf | |
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14 | .ft B |
| 15 | #include <stdlib.h> | |
| 16 | ||
| 17 | double | |
| 18 | atof(const char *nptr); | |
| 19 | .ft R | |
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20 | .fi |
| 21 | .SH DESCRIPTION | |
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22 | The |
| 23 | .I atof | |
| 24 | function converts the initial portion of the string pointed to by | |
| f11907db | 25 | .I nptr |
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26 | to |
| 27 | .I double | |
| 28 | representation. | |
| f11907db | 29 | .PP |
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30 | It is equivalent to: |
| 31 | .sp | |
| 32 | .RS | |
| 33 | strtod(nptr, (char **)NULL); | |
| 34 | .RE | |
| f11907db | 35 | .SH SEE ALSO |
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36 | atoi(3), atol(3), strtod(3), strtol(3), strtoul(3) |
| 37 | .SH STANDARDS | |
| 38 | .B Atof | |
| 39 | conforms to ANSI X3.159-1989 (``ANSI C''). | |
| f11907db | 40 | .SH BUGS |
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41 | This manual page represents intent instead of actual practice. |
| 42 | While it is intended that | |
| 43 | .I atof | |
| 44 | be implemented using | |
| 45 | .IR strtod (3), | |
| 46 | this has not yet happened. | |
| 47 | In the current system, | |
| 48 | .I atof | |
| 49 | translates a string in the following form to a double: | |
| 50 | an optional string of spaces, followed by an optional sign (``+'' or ``-''), | |
| 51 | followed by a string of digits which may contain a decimal point (``.''), | |
| 52 | followed by an optional exponent flag (``E'' or ``e''), followed by an | |
| 53 | optionally signed integer. |