tsort(1)						      General Commands Manual							  tsort(1)

NAME

       tsort - Sorts an unordered list of ordered pairs (topological sort)

SYNOPSIS

       tsort [file]

STANDARDS

       Interfaces documented on this reference page conform to industry standards as follows:

       tsort:  XCU5.0

       Refer to the standards(5) reference page for more information about industry standards and associated tags.

OPTIONS

       None

OPERANDS

       Pathname of a test file to be ordered.

	      If no file operand is specified, tsort reads standard input.

DESCRIPTION

       The  tsort  command reads from file or standard input an unordered list of ordered pairs, builds an ordered list, and writes it to standard
       output.

       [Tru64 UNIX]  For creating a subroutine library, do not use tsort; use the following command in its place:

       % ar -ts file.a

       The input file should contain pairs of nonempty strings separated by spaces.  Pairs of different items indicate a relative order.  Pairs of
       identical items indicate presence, but no relative order.

       [Tru64 UNIX]  You can use tsort to sort the output of the lorder command.

       [Tru64 UNIX]  If file contains an odd number of fields, tsort writes the error message:

       tsort:  Specify an even number of data fields.

NOTES

       The LC_COLLATE environment variable does not affect the actions of tsort.

EXIT STATUS

       The following exit values are returned: Successful completion.  An error occurred.

EXAMPLES

       To create a subroutine library, enter: lorder charin.o scanfld.o scan.o scanln.o      | tsort | xargs ar qv libsubs.a

       (Enter the command entirely on one line, not on two lines as shown above.)

       This creates a subroutine library named libsubs.a that contains charin.o, scanfld.o, scan.o, and scanln.o.  The ordering of the object mod-
       ules in the library is important.  The ld command requires each module to precede all the other modules that it calls or  references.   The
       lorder and tsort commands together add the subroutines to the library in the proper order.

       Suppose	that  scan.o calls scanfld.o and scanln.o.  scanfld.o also calls charin.o.  First, the lorder command creates a list of pairs that
       shows these dependencies:

       charin.o charin.o scanfld.o scanfld.o scan.o scan.o scanln.o scanln.o scanfld.o charin.o scanln.o charin.o scan.o scanfld.o

       Next, the | (vertical bar) sends this list to the tsort command, which converts it into the ordering you need:

       scan.o scanfld.o scanln.o charin.o

       Note that each module precedes the module it calls.  charin.o, which does not call another module, is last.

       The second | (vertical bar) then sends this list to xargs, which constructs and runs the following ar command:

       ar qv libsubs.a scan.o scanfld.o scanln.o charin.o

       This ar command creates the properly ordered library.

ENVIRONMENT VARIABLES

       The following environment variables affect the execution of tsort: Provides a default value for the internationalization variables that are
       unset or null. If LANG is unset or null, the corresponding value from the default locale is used.  If any of the internationalization vari-
       ables contain an invalid setting, the utility behaves as if none of the variables had been defined.  If set to a  non-empty  string  value,
       overrides  the  values of all the other internationalization variables.	Determines the locale for the interpretation of sequences of bytes
       of text data as characters (for example, single-byte as opposed to multibyte characters in arguments).  Determines the locale for the  for-
       mat  and  contents  of  diagnostic messages written to standard error.  Determines the location of message catalogues for the processing of
       LC_MESSAGES.

SEE ALSO

       Commands:  ar(1), lorder(1), xargs(1)

       Standards:  standards(5)

																	  tsort(1)