1 | /* |
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2 | FUNCTION |
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3 | <<fgetpos64>>---record position in a large stream or file |
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4 | |
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5 | INDEX |
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6 | fgetpos64 |
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7 | INDEX |
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8 | _fgetpos64_r |
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9 | |
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10 | SYNOPSIS |
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11 | #include <stdio.h> |
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12 | int fgetpos64(FILE *<[fp]>, _fpos64_t *<[pos]>); |
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13 | int _fgetpos64_r(struct _reent *<[ptr]>, FILE *<[fp]>, |
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14 | _fpos64_t *<[pos]>); |
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15 | |
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16 | DESCRIPTION |
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17 | Objects of type <<FILE>> can have a ``position'' that records how much |
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18 | of the file your program has already read. Many of the <<stdio>> functions |
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19 | depend on this position, and many change it as a side effect. |
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20 | |
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21 | You can use <<fgetpos64>> to report on the current position for a file |
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22 | identified by <[fp]> that was opened by <<fopen64>>; <<fgetpos>> will write |
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23 | a value representing that position at <<*<[pos]>>>. Later, you can |
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24 | use this value with <<fsetpos64>> to return the file to this |
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25 | position. |
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26 | |
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27 | In the current implementation, <<fgetpos64>> simply uses a character |
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28 | count to represent the file position; this is the same number that |
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29 | would be returned by <<ftello64>>. |
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30 | |
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31 | RETURNS |
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32 | <<fgetpos64>> returns <<0>> when successful. If <<fgetpos64>> fails, the |
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33 | result is <<1>>. Failure occurs on streams that do not support |
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34 | positioning or streams not opened via <<fopen64>>; the global <<errno>> |
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35 | indicates these conditions with the value <<ESPIPE>>. |
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36 | |
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37 | PORTABILITY |
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38 | <<fgetpos64>> is a glibc extension. |
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39 | |
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40 | No supporting OS subroutines are required. |
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41 | */ |
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42 | |
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43 | #include <stdio.h> |
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44 | |
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45 | #ifdef __LARGE64_FILES |
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46 | |
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47 | int |
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48 | _fgetpos64_r (struct _reent * ptr, |
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49 | FILE * fp, |
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50 | _fpos64_t * pos) |
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51 | { |
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52 | *pos = (_fpos64_t)_ftello64_r (ptr, fp); |
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53 | |
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54 | if (*pos != -1) |
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55 | { |
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56 | return 0; |
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57 | } |
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58 | return 1; |
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59 | } |
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60 | |
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61 | #ifndef _REENT_ONLY |
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62 | |
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63 | int |
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64 | fgetpos64 (FILE * fp, |
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65 | _fpos64_t * pos) |
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66 | { |
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67 | return _fgetpos64_r (_REENT, fp, pos); |
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68 | } |
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69 | |
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70 | #endif /* !_REENT_ONLY */ |
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71 | |
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72 | #endif /* __LARGE64_FILES */ |
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