Thank you for comment, please let me confirm... I guess, your point is something like: _AM_PROG_TAR is designed to prepare the command & options to emit a ustar bitstream from $(ustar), it is for "make dist" target, it is not for common use to find the "tar" or its compatible command. Thus, _AM_PROG_TAR should not be a classmate of AC_PROG_AWK or AC_PROG_SED, it should not be published to keep users from misleading. ...Is this correct?
If my guessing is correct, I have no objection about the difference of the purposes (of _AM_PROG_TAR and of AC_PROG_XXX), but I don't wish for AC_PROG_TAR as a shorthand of AC_CHECK_PROG([TAR],[tar],[tar]) or AC_PATH_PROG([TAR],[tar]). Sorry, my subject "for general use" made you feel like such? What I wish is exactly the command & its options to emit a ustar bitstream from a specified directory. I ought to have written as "... _AM_PROG_TAR for foreign 'make dist' target?" in subject. Even if the long name stating its scope, like, AM_PROG_FROM_TARDIR_TO_USTAR_STDOUT(), it is completely useful for my case. Regards, mpsuzuki On 2025/11/23 21:54, Bob Friesenhahn wrote:
Have you considered that a system may have multiple viable tar programs and that a user may prefer to use a different one than Automake chooses to use? Automake's criteria is different than a normal users and the program selected might not even be include 'tar' as part of its name. Bob On Sun, Nov 23, 2025, 12:54 AM mpsuzuki <[email protected]<mailto:[email protected]>> wrote: Dear experts, I'm interested in whether publishing _AM_PROG_TAR in tar.m4 for general use is a considerable idea, or bad idea. In my understanding, _AM_PROG_TAR is designed to help "make dist" of Automake target, and it is not for general use. There are some source packages whose top-level makefile is not managed by autoconf/automake and write their own "make dist" recipes. One example is FreeType. Currently it is hardcoding "tar --format=ustar -chf -", like: https://gitlab.freedesktop.org/freetype/freetype/-/blob/master/builds/toplevel.mk?ref_type=heads I hope its portability can be improved by something like _AM_PROG_TAR. It is not so difficult to reimplenetation of _AM_PROG_TAR in each software project, but if automake can consider publishising _AM_PROG_TAR, the maintenance would be easier. Regards, mpsuzuki
