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.TH GETHUGEPAGESIZES 3 "October 10, 2008"
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.SH NAME
gethugepagesizes - Get the system supported huge page sizes
.SH SYNOPSIS
.B #include <hugetlbfs.h>

.br
int gethugepagesizes(long pagesizes[], int n_elem);

.SH DESCRIPTION

The gethugepagesizes() function returns either the number of system supported
huge page sizes or the sizes  themselves. If \fBpagesizes\fP is NULL and
\fBn_elem\fP is 0, then the number of huge pages the system supports is
returned. Otherwise, \fBpagesizes\fP is filled with at most \fBn_elem\fP
page sizes.

.SH RETURN VALUE

On success, either the number of huge page sizes supported by the system or
the number of huge page sizes stored in pagesizes is returned. On failure,
-1 is returned and errno is set appropriately.

.SH ERRORS

.TP
.B EINVAL
\fBn_elem\fP is less than zero or \fBn_elem\fP is greater than zero and
\fBpagesizes\fP is NULL.
.PP
Also see opendir(3) for other possible values for errno. This error occurs
when the sysfs directory exists but cannot be opened.

.SH NOTES

This call will return all huge page sizes as reported by the kernel.
Not all of these sizes may be usable by the programmer since mount points
may not be available for all sizes.  To test whether a size will be usable
by \fBlibhugetlbfs\fP, hugetlbfs_find_path_for_size() can be called on a
specific size to see if a mount point is configured.

.SH SEE ALSO
.I oprofile(1),
.I opendir(3),
.I hugetlbfs_find_path_for_size(3),
.I libhugetlbfs(7)

.SH AUTHORS
libhugetlbfs was written by various people on the libhugetlbfs-devel
mailing list.