85 lines
2.3 KiB
Markdown
85 lines
2.3 KiB
Markdown
# PR_Seek
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Moves the current read-write file pointer by an offset expressed as a
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32-bit integer.
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:::{container} blockIndicator deprecated deprecatedHeader
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**Deprecated**
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This feature is no longer recommended. Though some browsers might
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still support it, it may have already been removed from the
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relevant web standards, may be in the process of being dropped, or
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may only be kept for compatibility purposes. Avoid using it, and
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update existing code if possible; see the
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[compatibility
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table](#Browser_compatibility)
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at the bottom of this page to
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guide your decision. Be aware that this feature may cease to work
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at any time.
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:::
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Deprecated in favor of {ref}`PR_Seek64`.
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## Syntax
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```{code}
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#include <prio.h>
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PRInt32 PR_Seek(
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PRFileDesc *fd,
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PRInt32 offset,
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PRSeekWhence whence);
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```
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## Parameters
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The function has the following parameters:
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`fd`
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: A pointer to a {ref}`PRFileDesc` object.
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`offset`
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: A value, in bytes, used with the whence parameter to set the file
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pointer. A negative value causes seeking in the reverse direction.
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`whence`
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: A value of type {ref}`PRSeekWhence` that specifies how to interpret the
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`offset` parameter in setting the file pointer associated with the
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fd parameter. The value for the `whence` parameter can be one of
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the following:
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> - `PR_SEEK_SET`. Sets the file pointer to the value of the
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> `offset` parameter.
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> - `PR_SEEK_CUR`. Sets the file pointer to its current location
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> plus the value of the `offset` parameter.
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> - `PR_SEEK_END`. Sets the file pointer to the size of the file
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> plus the value of the `offset` parameter.
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## Returns
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The function returns one of the following values:
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- If the function completes successfully, it returns the resulting file
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pointer location, measured in bytes from the beginning of the file.
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- If the function fails, the file pointer remains unchanged and the
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function returns -1. The error code can then be retrieved with
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{ref}`PR_GetError`.
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### Description
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Here's an idiom for obtaining the current location of the file pointer
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for the file descriptor `fd`:
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`PR_Seek(fd, 0, PR_SEEK_CUR)`
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### See Also
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If you need to move the file pointer by a large offset that's out of the
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range of a 32-bit integer, use {ref}`PR_Seek64`. New code should use
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{ref}`PR_Seek64` so that it can handle files larger than 2 GB.
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