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.TH mmap_shared 3
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.SH NAME
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mmap_shared \- memory map a file for reading and writing
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.SH SYNTAX
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.B #include <mmap.h>
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char* \fBmmap_shared\fP(const char* \fIfilename\fR,size_t* \fIfilesize\fR);
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.SH DESCRIPTION
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mmap_shared opens \fIfilename\fR for reading and writing, maps the
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whole file into memory, closes the file, writes the length of the file
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to \fIfilesize\fR and returns a pointer to the mapped file.
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The file is mapped shared. Changes done to the mapped region are
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written to disk and are visible to other processes reading from the file
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or mapping the same file into memory.
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The file is unmapped by the operating system if the process terminates.
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It can also be manually unmapped by calling \fBmunmap\fR from
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<sys/mman.h>.
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To write changes to disk immediately, you can use msync from
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<sys/mman.h>.
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If the file could not be opened or mapped, (void*)0 is returned.
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.SH "SEE ALSO"
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munmap(2), msync(2)
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