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diff --git a/man-pages-posix-2017/man1p/break.1p b/man-pages-posix-2017/man1p/break.1p new file mode 100644 index 0000000..4d8a486 --- /dev/null +++ b/man-pages-posix-2017/man1p/break.1p @@ -0,0 +1,223 @@ +'\" et +.TH BREAK "1P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" +.SH PROLOG +This manual page is part of the POSIX Programmer's Manual. +The Linux implementation of this interface may differ (consult +the corresponding Linux manual page for details of Linux behavior), +or the interface may not be implemented on Linux. +.\" +.SH NAME +break +\(em exit from for, while, or until loop +.SH SYNOPSIS +.LP +.nf +break \fB[\fIn\fB]\fR +.fi +.SH DESCRIPTION +If +.IR n +is specified, the +.IR break +utility shall exit from the +.IR n th +enclosing +.BR for , +.BR while , +or +.BR until +loop. If +.IR n +is not specified, +.IR break +shall behave as if +.IR n +was specified as 1. Execution shall continue with the command +immediately following the exited loop. The value of +.IR n +is a positive decimal integer. If +.IR n +is greater than the number of enclosing loops, the outermost enclosing +loop shall be exited. If there is no enclosing loop, the behavior is +unspecified. +.P +A loop shall enclose a +.IR break +or +.IR continue +command if the loop lexically encloses the command. A loop lexically +encloses a +.IR break +or +.IR continue +command if the command is: +.IP " *" 4 +Executing in the same execution environment (see +.IR "Section 2.12" ", " "Shell Execution Environment") +as the compound-list of the loop's do-group (see +.IR "Section 2.10.2" ", " "Shell Grammar Rules"), +and +.IP " *" 4 +Contained in a compound-list associated with the loop (either in the +compound-list of the loop's do-group or, if the loop is a +.BR while +or +.BR until +loop, in the compound-list following the +.BR while +or +.BR until +reserved word), and +.IP " *" 4 +Not in the body of a function whose function definition command (see +.IR "Section 2.9.5" ", " "Function Definition Command") +is contained in a compound-list associated with the loop. +.P +If +.IR n +is greater than the number of lexically enclosing loops and there is a +non-lexically enclosing loop in progress in the same execution +environment as the +.IR break +or +.IR continue +command, it is unspecified whether that loop encloses the command. +.SH OPTIONS +None. +.SH OPERANDS +See the DESCRIPTION. +.SH STDIN +Not used. +.SH "INPUT FILES" +None. +.SH "ENVIRONMENT VARIABLES" +None. +.SH "ASYNCHRONOUS EVENTS" +Default. +.SH STDOUT +Not used. +.SH STDERR +The standard error shall be used only for diagnostic messages. +.SH "OUTPUT FILES" +None. +.SH "EXTENDED DESCRIPTION" +None. +.SH "EXIT STATUS" +.IP "\00" 6 +Successful completion. +.IP >0 6 +The +.IR n +value was not an unsigned decimal integer greater than or equal to 1. +.SH "CONSEQUENCES OF ERRORS" +Default. +.LP +.IR "The following sections are informative." +.SH "APPLICATION USAGE" +None. +.SH EXAMPLES +.LP +.nf +for i in * +do + if test -d "$i" + then break + fi +done +.fi +.P +The results of running the following example are unspecified: there +are two loops in progress when the +.IR break +command is executed, and they are in the same execution environment, +but neither loop is lexically enclosing the +.IR break +command. (There are no loops lexically enclosing the +.IR continue +commands, either.) +.LP +.nf +foo() { + for j in 1 2; do + echo \(aqbreak 2\(aq >/tmp/do_break + echo " sourcing /tmp/do_break ($j)..." + # the behavior of the break from running the following command + # results in unspecified behavior: + . /tmp/do_break +.P + do_continue() { continue 2; } + echo " running do_continue ($j)..." + # the behavior of the continue in the following function call + # results in unspecified behavior (if execution reaches this + # point): + do_continue +.P + trap \(aqcontinue 2\(aq USR1 + echo " sending SIGUSR1 to self ($j)..." + # the behavior of the continue in the trap invoked from the + # following signal results in unspecified behavior (if + # execution reaches this point): + kill -s USR1 $$ + sleep 1 + done +} +for i in 1 2; do + echo "running foo ($i)..." + foo +done +.fi +.SH "RATIONALE" +In early proposals, consideration was given to expanding the syntax of +.IR break +and +.IR continue +to refer to a label associated with the appropriate loop as a +preferable alternative to the +.IR n +method. However, this volume of POSIX.1\(hy2017 does reserve the name space of command names +ending with a +<colon>. +It is anticipated that a future implementation could take advantage of +this and provide something like: +.sp +.RS 4 +.nf + +outofloop: for i in a b c d e +do + for j in 0 1 2 3 4 5 6 7 8 9 + do + if test -r "${i}${j}" + then break outofloop + fi + done +done +.fi +.P +.RE +.P +and that this might be standardized after implementation experience is +achieved. +.SH "FUTURE DIRECTIONS" +None. +.SH "SEE ALSO" +.IR "Section 2.14" ", " "Special Built-In Utilities" +.\" +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1-2017, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 7, 2018 Edition, +Copyright (C) 2018 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. +In the event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.opengroup.org/unix/online.html . +.PP +Any typographical or formatting errors that appear +in this page are most likely +to have been introduced during the conversion of the source files to +man page format. To report such errors, see +https://www.kernel.org/doc/man-pages/reporting_bugs.html . |