636 lines
14 KiB
Groff
636 lines
14 KiB
Groff
.\" Copyright (c) Michael Smith
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR Ohttp://wafu.netgate.net/tama/unix/indexe.htmlTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd June 22, 1998
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.Dt LIBSTAND 3
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.Os FreeBSD
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.Sh NAME
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.Nm libstand
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.Nd support library for standalone executables
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.Sh SYNOPSIS
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.Fd #include <stand.h>
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.Sh DESCRIPTION
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.Nm
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provides a set of supporting functions for standalone
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applications, mimicking where possible the standard BSD programming
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environment. The following sections group these functions by kind.
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Unless specifically described here, see the corresponding section 3
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manpages for the given functions.
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.Sh STRING FUNCTIONS
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String functions are available as documented in
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.Xr string 3
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and
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.Xr bstring 3 .
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.Sh MEMORY ALLOCATION
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.Bl -hang -width 10n
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.It Xo
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.Ft "void *"
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.Fn malloc "size_t size"
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.Xc
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.Pp
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Allocate
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.Fa size
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bytes of memory from the heap using a best-fit algorithm.
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.It Xo
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.Ft void
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.Fn free "void *ptr"
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.Xc
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.Pp
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Free the allocated object at
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.Fa ptr .
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.It Xo
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.Ft void
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.Fn setheap "void *start" "void *limit"
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.Xc
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.Pp
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Initialise the heap. This function must be called before calling
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.Fn alloc
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for the first time. The region between
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.Fa start
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and
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.Fa limit
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will be used for the heap; attempting to allocate beyond this will result
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in a panic.
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.It Xo
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.Ft "char *"
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.Fn sbrk "int junk"
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.Xc
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.Pp
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Provides the behaviour of
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.Fn sbrk 0 ,
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ie. returns the highest point that the heap has reached. This value can
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be used during testing to determine the actual heap usage. The
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.Fa junk
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argument is ignored.
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.El
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.Sh ENVIRONMENT
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A set of functions are provided for manipulating a flat variable space similar
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to the traditional shell-supported evironment. Major enhancements are support
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for set/unset hook functions.
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.Bl -hang -width 10n
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.It Xo
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.Ft "char *"
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.Fn getenv "const char *name"
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.Xc
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.It Xo
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.Ft int
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.Fn setenv "const char *name" "char *value" "int overwrite"
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.Xc
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.It Xo
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.Ft int
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.Fn putenv "const char *string"
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.Xc
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.It Xo
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.Ft int
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.Fn unsetenv "const char *name"
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.Xc
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.Pp
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These functions behave similarly to their standard library counterparts.
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.It Xo
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.Ft "struct env_var *"
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.Fn env_getenv "const char *name"
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.Xc
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.Pp
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Looks up a variable in the environment and returns its entire
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data structure.
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.It Xo
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.Ft int
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.Fn env_setenv "const char *name" "int flags" "char *value" "ev_sethook_t sethook" "ev_unsethook_t unsethook"
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.Xc
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.Pp
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Creates a new or sets an existing environment variable called
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.Fa name .
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If creating a new variable, the
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.Fa sethook
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and
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.Fa unsethook
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arguments may be specified.
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.Pp
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The set hook is invoked whenever an attempt
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is made to set the variable, unless the EV_NOHOOK flag is set. Typically
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a set hook will validate the
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.Fa value
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argument, and then call
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.Fn env_setenv
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again with EV_NOHOOK set to actually save the value. The predefined function
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.Fn env_noset
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may be specified to refuse all attempts to set a variable.
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.Pp
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The unset hook is invoked when an attempt is made to unset a variable.
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If it
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returns zero, the variable will be unset. The predefined function
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.Fa env_nounset
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may be used to prevent a variable being unset.
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.El
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.Sh STANDARD LIBRARY SUPPORT
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.Bl -hang -width 10n
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.It Xo
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.Ft int
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.Fn getopt "int argc" "char * const *argv" "cont char *optstring"
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.Xc
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.It Xo
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.Ft long
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.Fn strtol "const char *nptr" "char **endptr" "int base"
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.Xc
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.It Xo
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.Ft void
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.Fn srandom "unsigned long seed"
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.Xc
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.It Xo
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.Ft "unsigned long"
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.Fn random void
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.Xc
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.It Xo
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.Ft "char *"
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.Fn strerror "int error"
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.Xc
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.Pp
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Returns error messages for the subset of errno values supported by
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.Nm No .
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.It Fn assert expression
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.Pp
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Requires
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.Fd #include <assert.h>
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.It Xo
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.Ft int
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.Fn setjmp "jmp_buf env"
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.Xc
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.It Xo
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.Ft void
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.Fn longjmp "jmp_buf env" "int val"
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.Xc
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.Pp
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Defined as
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.Fn _setjmp
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and
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.Fn _lonjmp
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respectively as there is no signal state to manipulate. Requires
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.Fd #include <setjmp.h>
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.El
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.Sh CHARACTER I/O
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.Bl -hang -width 10n
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.It Xo
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.Ft void
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.Fn gets "char *buf"
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.Xc
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.Pp
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Read characters from the console into
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.Fa buf .
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All of the standard cautions apply to this function.
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.It Xo
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.Ft void
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.Fn ngets "char *buf" "size_t size"
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.Xc
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.Pp
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Read at most
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.Fa size
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- 1 characters from the console into
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.Fa buf .
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If
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.Fa size
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is less than 1, the function's behaviour is as for
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.Fn gets .
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.It Xo
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.Ft int
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.Fn fgetstr "char *buf" "int size" "int fd"
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.Xc
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.Pp
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Read a line of at most
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.Fa size
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characters into
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.Fa buf .
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Line terminating characters are stripped, and the buffer is always nul
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terminated. Returns the number of characters in
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.Fa buf
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if successful, or -1 if a read error occurs.
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.It Xo
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.Ft int
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.Fn printf "const char *fmt" "..."
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.Xc
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.It Xo
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.Ft void
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.Fn vprintf "const char *fmt" "va_list ap"
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.Xc
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.It Xo
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.Ft int
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.Fn sprintf "char *buf" "const char *fmt" "..."
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.Xc
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.It Xo
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.Ft void
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.Fn vsprintf "char *buf" "const char *fmt" "va_list ap"
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.Xc
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.Pp
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The *printf functions implement a subset of the standard
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.Fn printf
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family functionality and some extensions. The following standard conversions
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are supported: c,d,n,o,p,s,u,x. The following modifiers are supported:
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+,-,#,*,0,field width,precision,l.
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.Pp
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The
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.Li b
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conversion is provided to decode error registers. Its usage is:
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.Pp
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.Bd -ragged -offset indent
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printf(
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.Qq reg=%b\en ,
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regval,
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.Qq <base><arg>*
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);
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.Ed
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.Pp
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where <base> is the output expressed as a control character, eg. \e10 gives
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octal, \e20 gives hex. Each <arg> is a sequence of characters, the first of
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which gives the bit number to be inspected (origin 1) and the next characters
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(up to a character less than 32) give the text to be displayed if the bit is set.
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Thus
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.Pp
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.Bd -ragged -offset indent
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printf(
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.Qq reg=%b\en
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3
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.Qq \e10\e2BITTWO\e1BITONE\en
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);
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.Ed
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.Pp
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would give the output
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.Pp
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.Bd -ragged -offset indent
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reg=3<BITTWO,BITONE>
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.Ed
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.Pp
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The
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.Li D
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conversion provides a hexdump facility, eg.
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.Pp
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.Bd -ragged -offset indent
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printf(
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.Qq %6D ,
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ptr,
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.Qq \&:
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); gives
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.Qq XX:XX:XX:XX:XX:XX
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.Ed
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.Bd -ragged -offset indent
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printf(
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.Qq %*D ,
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len,
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ptr,
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.Qq "\ "
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); gives
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.Qq XX XX XX ...
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.Ed
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.El
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.Sh CHARACTER TESTS AND CONVERSIONS
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.Bl -hang -width 10n
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.It Xo
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.Ft int
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.Fn isupper "int c"
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.Xc
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.It Xo
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.Ft int
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.Fn islower "int c"
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.Xc
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.It Xo
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.Ft int
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.Fn isspace "int c"
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.Xc
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.It Xo
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.Ft int
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.Fn isdigit "int c"
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.Xc
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.It Xo
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.Ft int
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.Fn isxdigit "int c"
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.Xc
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.It Xo
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.Ft int
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.Fn isascii "int c"
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.Xc
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.It Xo
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.Ft int
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.Fn isalpha "int c"
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.Xc
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.It Xo
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.Ft int
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.Fn toupper "int c"
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.Xc
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.It Xo
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.Ft int
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.Fn tolower "int c"
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.Xc
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.El
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.Sh FILE I/O
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.Bl -hang -width 10n
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.It Xo
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.Ft int
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.Fn open "const char *path" "int flags"
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.Xc
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.Pp
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Similar to the behaviour as specified in
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.Xr open 2 ,
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except that file creation is not supported, so the mode parameter is not
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required. The
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.Fa flags
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argument may be one of O_RDONLY, O_WRONLY and O_RDWR (although no filesystems
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currently support writing).
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.It Xo
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.Ft int
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.Fn close "int fd"
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.Xc
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.It Xo
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.Ft void
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.Fn closeall void
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.Xc
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.Pp
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Close all open files.
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.It Xo
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.Ft ssize_t
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.Fn read "int fd" "void *buf" "size_t len"
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.Xc
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.It Xo
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.Ft ssize_t
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.Fn write "int fd" "void *buf" "size_t len"
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.Xc
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.Pp
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(No filesystems currently support writing.)
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.It Xo
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.Ft off_t
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.Fn lseek "int fd" "off_t offset" "int whence"
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.Xc
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.Pp
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Files being automatically uncompressed during reading cannot seek backwards
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from the current point.
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.It Xo
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.Ft int
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.Fn stat "const char *path" "struct stat *sb"
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.Xc
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.It Xo
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.Ft int
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.Fn fstat "int fd" "struct stat *sb"
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.Xc
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.Pp
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The
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.Fn stat
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and
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.Fn fstat
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functions only fill out the following fields in the
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.Fa sb
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structure: st_mode,st_nlink,st_uid,st_gid,st_size. The
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.Nm tftp
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filesystem cannot provide meaningful values for this call, and the
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.Nm cd9660
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filesystem always reports files having uid/gid of zero.
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.El
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.Sh PAGER
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.Nm
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supplies a simple internal pager to ease reading the output of large commands.
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.Bl -hang -width 10n
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.It Xo
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.Ft void
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.Fn pager_open
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.Xc
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.Pp
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Initialises the pager and tells it that the next line output will be the top of the
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display. The environment variable LINES is consulted to determine the number of
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lines to be displayed before pausing.
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.It Xo
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.Ft void
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.Fn pager_close void
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.Xc
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.Pp
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Closes the pager.
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.It Xo
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.Ft int
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.Fn pager_output "char *lines"
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.Xc
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.Pp
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Sends the lines in the nul-terminated buffer at
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.Fa lines
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to the pager. Newline characters are counted in order to determine the number
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of lines being output (wrapped lines are not accounted for).
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.Fn pager_output
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will return zero when all of the lines have been output, or nonzero if the
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display was paused and the user elected to quit.
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.It Xo
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.Ft int
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.Fn pager_file "char *fname"
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.Xc
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.Pp
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Attempts to open and display the file
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.Fa fname .
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Returns -1 on error, 0 at EOF, or 1 if the user elects to quit while reading.
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.El
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.Sh MISC
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.Bl -hang -width 10n
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.It Xo
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.Ft void
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.Fn twiddle void
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.Xc
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.Pp
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Successive calls emit the characters in the sequence |,/,-,\\ followed by a
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backspace in order to provide reassurance to the user.
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.El
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.Sh REQUIRED LOW-LEVEL SUPPORT
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The following resources are consumed by
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.Nm
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- stack, heap, console and devices.
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.Pp
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The stack must be established before
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.Nm
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functions can be invoked. Stack requirements vary depending on the functions
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and filesystems used by the consumer and the support layer functions detailed
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below.
|
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.Pp
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The heap must be established before calling
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.Fn alloc
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or
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.Fn open
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by calling
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.Fn setheap .
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Heap usage will vary depending on the number of simultaneously open files,
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as well as client behaviour. Automatic decompression will allocate more
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than 64K of data per open file.
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.Pp
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|
Console access is performed via the
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.Fn getchar ,
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.Fn putchar
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and
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.Fn ischar
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|
functions detailed below.
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.Pp
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Device access is initiated via
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.Fn devopen
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and is performed through the
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.Fn dv_strategy ,
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.Fn dv_ioctl
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and
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.Fn dv_close
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functions in the device switch structure that
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.Fn devopen
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returns.
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.Pp
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The consumer must provide the following support functions:
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.Bl -hang -width 10n
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.It Xo
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.Ft int
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.Fn getchar void
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.Xc
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.Pp
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Return a character from the console, used by
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.Fn gets ,
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.Fn ngets
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and pager functions.
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.It Xo
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.Ft int
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.Fn ischar void
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.Xc
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.Pp
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Returns nonzero if a character is waiting from the console.
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.It Xo
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.Ft void
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.Fn putchar int
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.Xc
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.Pp
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Write a character to the console, used by
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.Fn gets ,
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.Fn ngets ,
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.Fn *printf ,
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.Fn panic
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and
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.Fn twiddle
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and thus by many other functions for debugging and informational output.
|
|
.It Xo
|
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.Ft int
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.Fn devopen "struct open_file *of" "const char *name" "char **file"
|
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.Xc
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.Pp
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Open the appropriate device for the file named in
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.Fa name ,
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returning in
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.Fa file
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a pointer to the remaining body of
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.Fa name
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which does not refer to the device. The
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.Va f_dev
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field in
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.Fa of
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will be set to point to the
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.Vt devsw
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structure for the opened device if successful. Device identifiers must
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always precede the path component, but may otherwise be arbitrarily formatted.
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Used by
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.Fn open
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and thus for all device-related I/O.
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.It Xo
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.Ft int
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.Fn devclose "struct open_file *of"
|
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.Xc
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|
Close the device allocated for
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.Fa of .
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|
The device driver itself will already have been called for the close; this call
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|
should clean up any allocation made by devopen only.
|
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.It Xo
|
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.Ft void
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|
.Fn panic "const char *msg" "..."
|
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.Xc
|
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.Pp
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|
Signal a fatal and unrecoverable error condition. The
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.Fa msg ...
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arguments are as for
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.Fn printf .
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.El
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.Sh INTERNAL FILESYSTEMS
|
|
Internal filesystems are enabled by the consumer exporting the array
|
|
.Vt struct fs_ops *file_system[] ,
|
|
which should be initialised with pointers
|
|
to
|
|
.Vt struct fs_ops
|
|
structures. The following filesystem handlers are supplied by
|
|
.Nm No ,
|
|
the consumer may supply other filesystems of their own:
|
|
.Bl -hang -width "cd9660_fsops "
|
|
.It ufs_fsops
|
|
The BSD UFS.
|
|
.It ext2fs_fsops
|
|
Linux ext2fs filesystem.
|
|
.It tftp_fsops
|
|
File access via TFTP.
|
|
.It nfs_fsops
|
|
File access via NFS.
|
|
.It cd9660_fsops
|
|
ISO 9660 (CD-ROM) filesystem.
|
|
.It zipfs_fsops
|
|
Stacked filesystem supporting gzipped files.
|
|
When trying the zipfs filesystem,
|
|
.Nm
|
|
appends
|
|
.Li .gz
|
|
to the end of the filename, and then tries to locate the file using the other
|
|
filesystems. Placement of this filesystem in the
|
|
.Va file_system[]
|
|
array determines whether gzipped files will be opened in preference to non-gzipped
|
|
files. It is only possible to seek a gzipped file forwards, and
|
|
.Fn stat
|
|
and
|
|
.Fn fstat
|
|
on gzipped files will report an invalid length.
|
|
.El
|
|
.Pp
|
|
The array of
|
|
.Vt struct fs_ops
|
|
pointers should be terminated with a NULL.
|
|
.Sh DEVICES
|
|
Devices are exported by the supporting code via the array
|
|
.Vt struct devsw *devsw[]
|
|
which is a NULL terminated array of pointers to device switch structures.
|
|
.Sh BUGS
|
|
.Pp
|
|
The lack of detailed memory usage data is unhelpful.
|
|
.Sh HISTORY
|
|
.Nm
|
|
contains contributions from many sources, including:
|
|
.Bl -bullet -compact
|
|
.It
|
|
.Nm libsa
|
|
from
|
|
.Nx
|
|
.It
|
|
.Nm libc
|
|
and
|
|
.Nm libkern
|
|
from
|
|
.Fx 3.0 .
|
|
.It
|
|
.Nm zalloc
|
|
from
|
|
.An Matthew Dillon Aq dillon@backplane.com
|
|
.El
|
|
.Pp
|
|
The reorganisation and port to
|
|
.Fx 3.0 ,
|
|
the environment functions and this manpage were written by
|
|
.An Mike Smith Aq msmith@freebsd.org .
|