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gcc-2.95.3 Linux下最常用的C编译器

DEFDOC (ITIME, "Get local time of day.", "\
Returns the current local time hour, minutes, and seconds in elements
1, 2, and 3 of @var{@1@}, respectively.
")

DEFDOC (MCLOCK, "Get number of clock ticks for process.", "\
Returns the number of clock ticks since the start of the process.
Supported on systems with @code{clock(3)} (q.v.).

@cindex wraparound, timings
@cindex limits, timings
This intrinsic is not fully portable, such as to systems
with 32-bit @code{INTEGER} types but supporting times
wider than 32 bits.
Therefore, the values returned by this intrinsic
might be, or become, negative,
or numerically less than previous values,
during a single run of the compiled program.

@xref{MClock8 Intrinsic}, for information on a
similar intrinsic that might be portable to more
GNU Fortran implementations, though to fewer
Fortran compilers.

If the system does not support @code{clock(3)},
-1 is returned.
")

DEFDOC (MCLOCK8, "Get number of clock ticks for process.", "\
Returns the number of clock ticks since the start of the process.
Supported on systems with @code{clock(3)} (q.v.).

@cindex wraparound, timings
@cindex limits, timings
@emph{Warning:} this intrinsic does not increase the range
of the timing values over that returned by @code{clock(3)}.
On a system with a 32-bit @code{clock(3)},
@code{@0@} will return a 32-bit value,
even though converted to an @samp{INTEGER(KIND=2)} value.
That means overflows of the 32-bit value can still occur.
Therefore, the values returned by this intrinsic
might be, or become, negative,
or numerically less than previous values,
during a single run of the compiled program.

No Fortran implementations other than GNU Fortran are
known to support this intrinsic at the time of this
writing.
@xref{MClock Intrinsic}, for information on a
similar intrinsic that might be portable to more Fortran
compilers, though to fewer GNU Fortran implementations.

If the system does not support @code{clock(3)},
-1 is returned.
")

DEFDOC (SECNDS, "Get local time offset since midnight.", "\
Returns the local time in seconds since midnight minus the value
@var{@1@}.

@cindex wraparound, timings
@cindex limits, timings
This values returned by this intrinsic
become numerically less than previous values
(they wrap around) during a single run of the
compiler program, under normal circumstances
(such as running through the midnight hour).
")

DEFDOC (SECOND_func, "Get CPU time for process in seconds.", "\
Returns the process's runtime in seconds---the same value as the
UNIX function @code{etime} returns.

@cindex wraparound, timings
@cindex limits, timings
On some systems, the underlying timings are represented
using types with sufficiently small limits that overflows
(wraparounds) are possible, such as 32-bit types.
Therefore, the values returned by this intrinsic
might be, or become, negative,
or numerically less than previous values,
during a single run of the compiled program.
")

DEFDOC (SECOND_subr, "Get CPU time for process@99@in seconds.", "\
Returns the process's runtime in seconds in @var{@1@}---the same value
as the UNIX function @code{etime} returns.

@cindex wraparound, timings
@cindex limits, timings
On some systems, the underlying timings are represented
using types with sufficiently small limits that overflows
(wraparounds) are possible, such as 32-bit types.
Therefore, the values returned by this intrinsic
might be, or become, negative,
or numerically less than previous values,
during a single run of the compiled program.

This routine is known from Cray Fortran.  @xref{CPU_Time Intrinsic},
for a standard equivalent.
")

DEFDOC (SYSTEM_CLOCK, "Get current system clock value.", "\
Returns in @var{@1@} the current value of the system clock; this is
the value returned by the UNIX function @code{times(2)}
in this implementation, but
isn't in general.
@var{@2@} is the number of clock ticks per second and
@var{@3@} is the maximum value this can take, which isn't very useful
in this implementation since it's just the maximum C @code{unsigned
int} value.

@cindex wraparound, timings
@cindex limits, timings
On some systems, the underlying timings are represented
using types with sufficiently small limits that overflows
(wraparounds) are possible, such as 32-bit types.
Therefore, the values returned by this intrinsic
might be, or become, negative,
or numerically less than previous values,
during a single run of the compiled program.
")

DEFDOC (CPU_TIME, "Get current CPU time.", "\
Returns in @var{@1@} the current value of the system time.
This implementation of the Fortran 95 intrinsic is just an alias for
@code{second} @xref{Second Intrinsic (subroutine)}.

@cindex wraparound, timings
@cindex limits, timings
On some systems, the underlying timings are represented
using types with sufficiently small limits that overflows
(wraparounds) are possible, such as 32-bit types.
Therefore, the values returned by this intrinsic
might be, or become, negative,
or numerically less than previous values,
during a single run of the compiled program.
")

DEFDOC (TIME8, "Get current time as time value.", "\
Returns the current time encoded as a long integer
(in the manner of the UNIX function @code{time(3)}).
This value is suitable for passing to @code{CTIME},
@code{GMTIME}, and @code{LTIME}.

@cindex wraparound, timings
@cindex limits, timings
@emph{Warning:} this intrinsic does not increase the range
of the timing values over that returned by @code{time(3)}.
On a system with a 32-bit @code{time(3)},
@code{@0@} will return a 32-bit value,
even though converted to an @samp{INTEGER(KIND=2)} value.
That means overflows of the 32-bit value can still occur.
Therefore, the values returned by this intrinsic
might be, or become, negative,
or numerically less than previous values,
during a single run of the compiled program.

No Fortran implementations other than GNU Fortran are
known to support this intrinsic at the time of this
writing.
@xref{Time Intrinsic (UNIX)}, for information on a
similar intrinsic that might be portable to more Fortran
compilers, though to fewer GNU Fortran implementations.
")

DEFDOC (TIME_unix, "Get current time as time value.", "\
Returns the current time encoded as an integer
(in the manner of the UNIX function @code{time(3)}).
This value is suitable for passing to @code{CTIME},
@code{GMTIME}, and @code{LTIME}.

@cindex wraparound, timings
@cindex limits, timings
This intrinsic is not fully portable, such as to systems
with 32-bit @code{INTEGER} types but supporting times
wider than 32 bits.
Therefore, the values returned by this intrinsic
might be, or become, negative,
or numerically less than previous values,
during a single run of the compiled program.

@xref{Time8 Intrinsic}, for information on a
similar intrinsic that might be portable to more
GNU Fortran implementations, though to fewer
Fortran compilers.
")

#define BES(num,n,val) "\
Calculates the Bessel function of the " #num " kind of \
order " #n " of @var{@" #val "@}.\n\
See @code{bessel(3m)}, on whose implementation the \
function depends.\
"

DEFDOC (BESJ0, "Bessel function.", BES (first, 0, 1))
DEFDOC (BESJ1, "Bessel function.", BES (first, 1, 1))
DEFDOC (BESJN, "Bessel function.", BES (first, @var{N}, 2))
DEFDOC (BESY0, "Bessel function.", BES (second, 0, 1))
DEFDOC (BESY1, "Bessel function.", BES (second, 1, 1))
DEFDOC (BESYN, "Bessel function.", BES (second, @var{N}, 2))
DEFDOC (DBESJ0, "Bessel function (archaic).", ARCHAIC (BESJ0, BesJ0))
DEFDOC (DBESJ1, "Bessel function (archaic).", ARCHAIC (BESJ1, BesJ1))
DEFDOC (DBESJN, "Bessel function (archaic).", ARCHAIC_2nd (BESJN, BesJN))
DEFDOC (DBESY0, "Bessel function (archaic).", ARCHAIC (BESY0, BesY0))
DEFDOC (DBESY1, "Bessel function (archaic).", ARCHAIC (BESY1, BesY1))
DEFDOC (DBESYN, "Bessel function (archaic).", ARCHAIC_2nd (BESYN, BesYN))

DEFDOC (ERF, "Error function.", "\
Returns the error function of @var{@1@}.
See @code{erf(3m)}, which provides the implementation.
")

DEFDOC (ERFC, "Complementary error function.", "\
Returns the complementary error function of @var{@1@}:
@samp{ERFC(R) = 1 - ERF(R)} (except that the result might be more
accurate than explicitly evaluating that formulae would give).
See @code{erfc(3m)}, which provides the implementation.
")

DEFDOC (DERF, "Error function (archaic).", ARCHAIC (ERF, ErF))
DEFDOC (DERFC, "Complementary error function (archaic).", ARCHAIC (ERFC, ErFC))

DEFDOC (IRAND, "Random number.", "\
Returns a uniform quasi-random number up to a system-dependent limit.
If @var{@1@} is 0, the next number in sequence is returned; if
@var{@1@} is 1, the generator is restarted by calling the UNIX function
@samp{srand(0)}; if @var{@1@} has any other value,
it is used as a new seed with @code{srand()}.

@xref{SRand Intrinsic}.

@emph{Note:} As typically implemented (by the routine of the same
name in the C library), this random number generator is a very poor
one, though the BSD and GNU libraries provide a much better
implementation than the `traditional' one.
On a different system you almost certainly want to use something better.
")

DEFDOC (RAND, "Random number.", "\
Returns a uniform quasi-random number between 0 and 1.
If @var{@1@} is 0, the next number in sequence is returned; if
@var{@1@} is 1, the generator is restarted by calling @samp{srand(0)};
if @var{@1@} has any other value, it is used as a new seed with
@code{srand}.

@xref{SRand Intrinsic}.

@emph{Note:} As typically implemented (by the routine of the same
name in the C library), this random number generator is a very poor
one, though the BSD and GNU libraries provide a much better
implementation than the `traditional' one.
On a different system you
almost certainly want to use something better.
")

DEFDOC (SRAND, "Random seed.", "\
Reinitialises the generator with the seed in @var{@1@}.
@xref{IRand Intrinsic}.
@xref{Rand Intrinsic}.
")

DEFDOC (ACCESS, "Check file accessibility.", "\
Checks file @var{@1@} for accessibility in the mode specified by @var{@2@} and
returns 0 if the file is accessible in that mode, otherwise an error
code if the file is inaccessible or @var{@2@} is invalid.
See @code{access(2)}.
A null character (@samp{CHAR(0)}) marks the end of
the name in @var{@1@}---otherwise,
trailing blanks in @var{@1@} are ignored.
@var{@2@} may be a concatenation of any of the following characters:

@table @samp
@item r
Read permission

@item w
Write permission

@item x
Execute permission

@item @kbd{SPC}
Existence
@end table
")

DEFDOC (CHDIR_subr, "Change directory.", "\
Sets the current working directory to be @var{@1@}.
If the @var{@2@} argument is supplied, it contains 0
on success or a non-zero error code otherwise upon return.
See @code{chdir(3)}.

@emph{Caution:} Using this routine during I/O to a unit connected with a
non-absolute file name can cause subsequent I/O on such a unit to fail
because the I/O library might reopen files by name.

Some non-GNU implementations of Fortran provide this intrinsic as
only a function, not as a subroutine, or do not support the
(optional) @var{@2@} argument.
")

DEFDOC (CHDIR_func, "Change directory.", "\
Sets the current working directory to be @var{@1@}.
Returns 0 on success or a non-zero error code.
See @code{chdir(3)}.

@emph{Caution:} Using this routine during I/O to a unit connected with a
non-absolute file name can cause subsequent I/O on such a unit to fail
because the I/O library might reopen files by name.

Due to the side effects performed by this intrinsic, the function
form is not recommended.
")

DEFDOC (CHMOD_func, "Change file modes.", "\
Changes the access mode of file @var{@1@} according to the
specification @var{@2@}, which is given in the format of
@code{chmod(1)}.
A null character (@samp{CHAR(0)}) marks the end of
the name in @var{@1@}---otherwise,
trailing blanks in @var{@1@} are ignored.
Currently, @var{@1@} must not contain the single quote
character.

Returns 0 on success or a non-zero error code otherwise.

Note that this currently works
by actually invoking @code{/bin/chmod} (or the @code{chmod} found when
the library was configured) and so might fail in some circumstances and
will, anyway, be slow.

Due to the side effects performed by this intrinsic, the function
form is not recommended.
")

DEFDOC (CHMOD_subr, "Change file modes.", "\
Changes the access mode of file @var{@1@} according to the
specification @var{@2@}, which is given in the format of
@code{chmod(1)}.
A null character (@samp{CHAR(0)}) marks the end of
the name in @var{@1@}---otherwise,
trailing blanks in @var{@1@} are ignored.
Currently, @var{@1@} must not contain the single quote
character.

If the @var{@3@} argument is supplied, it contains
0 on success or a non-zero error code upon return.

Note that this currently works
by actually invoking @code{/bin/chmod} (or the @code{chmod} found when
the library was configured) and so might fail in some circumstances and
will, anyway, be slow.

Some non-GNU implementations of Fortran provide this intrinsic as
only a function, not as a subroutine, or do not support the
(optional) @var{@3@} argument.
")

DEFDOC (GETCWD_func, "Get current working directory.", "\
Places the current working directory in @var{@1@}.
Returns 0 on
success, otherwise a non-zero error code
(@code{ENOSYS} if the system does not provide @code{getcwd(3)}
or @code{getwd(3)}).
")

DEFDOC (GETCWD_subr, "Get current working directory.", "\
Places the current working directory in @var{@1@}.
If the @var{@2@} argument is supplied, it contains 0
success or a non-zero error code upon return
(@code{ENOSYS} if the system does not provide @code{getcwd(3)}
or @code{getwd(3)}).

Some non-GNU implementations of Fortran provide this intrinsic as
only a function, not as a subroutine, or do not support the
(optional) @var{@2@} argument.
")

DEFDOC (FSTAT_func, "Get file information.", "\
Obtains data about the file open on Fortran I/O unit @var{@1@} and
places them in the array @var{@2@}.
The values in this array are
extracted from the @code{stat} structure as returned by
@code{fstat(2)} q.v., as follows:

@enumerate
@item
Device ID

@item
Inode number

@item
File mode

@item
Number of links

@item
Owner's uid

@item
Owner's gid

@item
ID of device containing directory entry for file
(0 if not available)

@item
File size (bytes)

@item
Last access time

@item
Last modification time

@item
Last file status change time

@item
Preferred I/O block size (-1 if not available)

@item
Number of blocks allocated (-1 if not available)
@end enumerate

Not all these elements are relevant on all systems.
If an element is not relevant, it is returned as 0.

Returns 0 on success or a non-zero error code.
")

DEFDOC (FSTAT_subr, "Get file information.", "\
Obtains data about the file open on Fortran I/O unit @var{@1@} and
places them in the array @var{@2@}.
The values in this array are
extracted from the @code{stat} structure as returned by
@code{fstat(2)} q.v., as follows:

@enumerate
@item