TSORT(1,C) AIX Commands Reference TSORT(1,C) ------------------------------------------------------------------------------- tsort PURPOSE Sorts an unordered list of ordered pairs (a topological sort). SYNTAX +--------+ tsort ---| |---| +- file -+ DESCRIPTION The tsort command reads from file or standard input an unordered list of ordered pairs, it builds a completely ordered list, and writes it to standard output. The input file should contain pairs of non-empty strings separated by blanks. Pairs of different items indicate a relative order. Pairs of identical items indicate presence, but no relative order. You can use tsort to sort the output of the lorder command. If file contains an odd number of fields, tsort writes the error message "Odd data". EXAMPLE To create a subroutine library: lorder charin.o scanfld.o scan.o scanln.o | tsort | xargs ar qv libsubs.a This creates a subroutine library named "libsubs.a" that contains "charin.o", "scanfld.o", "scan.o", and "scanln.o". The ordering of the object modules 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: Processed November 8, 1990 TSORT(1,C) 1 TSORT(1,C) AIX Commands Reference TSORT(1,C) charin.o charin.o scanfld.o scanfld.o scan.o scan.o scanln.o scanln.o scanfld.o charin.o scan.o scanfld.o scan.o scanln.o Next, the "|" (vertical bar) sends this list to the tsort command, which converts it into the ordering we need: scan.o scanfld.o scanln.o charin.o Each module precedes the module it calls. "charin.o", which does not call another module, is last. The second "|" 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. RELATED INFORMATION See the following commands: "ar," "lorder," and "xargs." Processed November 8, 1990 TSORT(1,C) 2