[444] | 1 | /* |
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| 2 | * Copyright (c) 1990 The Regents of the University of California. |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms are permitted |
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| 6 | * provided that the above copyright notice and this paragraph are |
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| 7 | * duplicated in all such forms and that any documentation, |
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| 8 | * advertising materials, and other materials related to such |
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| 9 | * distribution and use acknowledge that the software was developed |
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| 10 | * by the University of California, Berkeley. The name of the |
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| 11 | * University may not be used to endorse or promote products derived |
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| 12 | * from this software without specific prior written permission. |
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| 13 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
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| 14 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
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| 15 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
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| 16 | */ |
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| 17 | |
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| 18 | /* |
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| 19 | FUNCTION |
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| 20 | <<fgetpos>>---record position in a stream or file |
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| 21 | |
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| 22 | INDEX |
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| 23 | fgetpos |
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| 24 | INDEX |
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| 25 | _fgetpos_r |
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| 26 | |
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| 27 | SYNOPSIS |
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| 28 | #include <stdio.h> |
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| 29 | int fgetpos(FILE *restrict <[fp]>, fpos_t *restrict <[pos]>); |
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| 30 | int _fgetpos_r(struct _reent *<[ptr]>, FILE *restrict <[fp]>, fpos_t *restrict <[pos]>); |
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| 31 | |
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| 32 | DESCRIPTION |
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| 33 | Objects of type <<FILE>> can have a ``position'' that records how much |
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| 34 | of the file your program has already read. Many of the <<stdio>> functions |
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| 35 | depend on this position, and many change it as a side effect. |
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| 36 | |
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| 37 | You can use <<fgetpos>> to report on the current position for a file |
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| 38 | identified by <[fp]>; <<fgetpos>> will write a value |
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| 39 | representing that position at <<*<[pos]>>>. Later, you can |
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| 40 | use this value with <<fsetpos>> to return the file to this |
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| 41 | position. |
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| 42 | |
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| 43 | In the current implementation, <<fgetpos>> simply uses a character |
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| 44 | count to represent the file position; this is the same number that |
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| 45 | would be returned by <<ftell>>. |
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| 46 | |
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| 47 | RETURNS |
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| 48 | <<fgetpos>> returns <<0>> when successful. If <<fgetpos>> fails, the |
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| 49 | result is <<1>>. Failure occurs on streams that do not support |
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| 50 | positioning; the global <<errno>> indicates this condition with the |
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| 51 | value <<ESPIPE>>. |
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| 52 | |
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| 53 | PORTABILITY |
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| 54 | <<fgetpos>> is required by the ANSI C standard, but the meaning of the |
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| 55 | value it records is not specified beyond requiring that it be |
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| 56 | acceptable as an argument to <<fsetpos>>. In particular, other |
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| 57 | conforming C implementations may return a different result from |
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| 58 | <<ftell>> than what <<fgetpos>> writes at <<*<[pos]>>>. |
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| 59 | |
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| 60 | No supporting OS subroutines are required. |
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| 61 | */ |
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| 62 | |
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| 63 | #include <_ansi.h> |
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| 64 | #include <reent.h> |
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| 65 | #include <stdio.h> |
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| 66 | |
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| 67 | int |
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| 68 | _fgetpos_r (struct _reent * ptr, |
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| 69 | FILE *__restrict fp, |
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| 70 | _fpos_t *__restrict pos) |
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| 71 | { |
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| 72 | *pos = _ftell_r (ptr, fp); |
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| 73 | |
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| 74 | if (*pos != -1) |
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| 75 | { |
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| 76 | return 0; |
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| 77 | } |
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| 78 | return 1; |
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| 79 | } |
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| 80 | |
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| 81 | #ifndef _REENT_ONLY |
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| 82 | |
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| 83 | int |
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| 84 | fgetpos (FILE *__restrict fp, |
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| 85 | _fpos_t *__restrict pos) |
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| 86 | { |
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| 87 | return _fgetpos_r (_REENT, fp, pos); |
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| 88 | } |
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| 89 | |
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| 90 | #endif /* !_REENT_ONLY */ |
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