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2012-11-14 21:35:20 +00:00
< p > Library Version 11.2.5.3< / p >
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< th colspan = "3" align = "center" > db_env_set_func_ioinfo< / th >
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< th width = "60%" align = "center" > Appendix
Berkeley DB Application Space Static Functions
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< h2 class = "title" style = "clear: both" > < a id = "db_env_set_func_ioinfo" > < / a > db_env_set_func_ioinfo< / h2 >
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< pre class = "programlisting" > #include < db.h>
int
db_env_set_func_ioinfo(int (*func_ioinfo)(const char *path,
int fd, u_int32_t *mbytesp, u_int32_t *bytesp, u_int32_t *iosizep)); < / pre >
< p >
The Berkeley DB library requires the ability to determine the size and
I/O characteristics of a file.
< / p >
< p >
The < code class = "function" > db_env_set_func_ioinfo()< / code > function configures all operations performed
by a process and all of its threads of control, not operations
confined to a single database environment.
< / p >
< p >
Although the < code class = "function" > db_env_set_func_ioinfo()< / code > function may be called at any time
during the life of the application, it should normally be called
before making calls to the < a class = "xref" href = "envcreate.html" title = "db_env_create" > db_env_create< / a > or
< a class = "xref" href = "dbcreate.html" title = "db_create" > db_create< / a > methods.
< / p >
< p >
The < code class = "function" > db_env_set_func_ioinfo()< / code > < span >
function returns a non-zero error value on failure and 0 on success.
< / span >
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< h3 class = "title" > < a id = "idp63597008" > < / a > Parameters< / h3 >
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< h4 class = "title" > < a id = "idp63597200" > < / a > func_ioinfo< / h4 >
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The < span class = "bold" > < strong > func_ioinfo< / strong > < / span > parameter is the
function which returns the size and I/O characteristics of a file.
< / p >
< p >
The < span class = "bold" > < strong > path< / strong > < / span > parameter is the pathname of
the file to be checked, and the < span class = "bold" > < strong > fd< / strong > < / span >
parameter is an open file descriptor on the file.
< / p >
< p >
If the < span class = "bold" > < strong > mbytesp< / strong > < / span > and < span class = "bold" > < strong > bytesp< / strong > < / span > parameters are non-NULL, the < span class = "bold" > < strong > ioinfo< / strong > < / span > function must return in them the size of
the file: the number of megabytes in the file into the memory location
to which the < span class = "bold" > < strong > mbytesp< / strong > < / span > parameter
refers, and the number of bytes over and above that number of
megabytes into the memory location to which the < span class = "bold" > < strong > bytesp< / strong > < / span > parameter refers.
< / p >
< p >
In addition, if the < span class = "bold" > < strong > iosizep< / strong > < / span > parameter
is non-NULL, the < span class = "bold" > < strong > ioinfo< / strong > < / span > function must
return the optimum granularity for I/O operations to the file into the
memory location to which it refers.
< / p >
< p >
The < span class = "bold" > < strong > func_ioinfo< / strong > < / span > function must return
the value of < span class = "bold" > < strong > errno< / strong > < / span > on failure and 0
on success.
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< h3 class = "title" > < a id = "idp63591736" > < / a > See Also< / h3 >
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< a href = "../../programmer_reference/program_runtime.html" class = "olink" > Run-time configuration< / a >
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