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author | Eric Blake <eblake@redhat.com> | 2015-04-15 16:31:34 -0600 |
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committer | Eric Blake <eblake@redhat.com> | 2015-04-21 06:15:35 -0600 |
commit | 76754e04fce5f6a7701bec57b057020585df2ae3 (patch) | |
tree | dc367be3756d07fa8f3b644bc6f8f7b50f5099e4 /tests/base.at | |
parent | 7bc2c5623d2fed6421bf95279e5d610ed8dbaa50 (diff) | |
download | autoconf-76754e04fce5f6a7701bec57b057020585df2ae3.tar.gz |
lib: use shorter way to test if variable is set
Based on an idea by Bernhard Reutner-Fischer.
We frequently used the idiom of 'test "${var+set}" = set' to
test if $var was set to a non-empty string, but this can portably
be trimmed to a more compact 'test ${var+y}' for a smaller
configure file. Testing that a variable is not set can be done
with '${var+false} :' (although the value of $? is not reliably
1 when the variable is set).
The code for AS_VAR_TEST_SET already used the form '${var+:} false',
but it is slightly longer, and does not guarantee $? of 1.
Tested on coreutils, where the resulting configure file is about
1k smaller.
* doc/autoconf.texi (Shell Substitutions): Prefer shorter sequence
for testing if a variable is set.
(Limitations of Builtins) <test (strings)>: Document it.
* configure.ac: Use it.
* lib/autoconf/c.m4 (_AC_PROG_CC_G, _AC_PROG_CXX_G)
(_AC_PROG_OBJC_G, _AC_PROG_OBJCXX_G): Likewise.
* lib/autoconf/fortran.m4 (_AC_PROG_FC_G): Likewise.
* lib/autoconf/general.m4 (_AC_ENABLE_IF_ACTION, AC_CACHE_SAVE):
Likewise.
* lib/autoconf/lang.m4 (_AC_COMPILER_EXEEXT_DEFAULT): Likewise.
* lib/autoconf/programs.m4 (AC_PROG_INSTALL, AC_PROG_MKDIR_P)
(_AC_PROG_LEX_YYTEXT_DECL): Likewise.
* lib/autoconf/status.m4 (_AC_OUTPUT_MAIN_LOOP): Likewise.
* lib/autotest/general.m4 (AT_INIT): Likewise.
* tests/base.at (AC_CACHE_CHECK): Likewise.
* tests/m4sh.at (LINENO): Likewise.
* lib/m4sugar/m4sh.m4 (_AS_BOURNE_COMPATIBLE)
(_AS_DETECT_BETTER_SHELL, _AS_SHELL_SANITIZE)
(_AS_PATH_SEPARATOR_PREPARE): Likewise.
(AS_VAR_TEST_SET): Use shorter sequence.
Signed-off-by: Eric Blake <eblake@redhat.com>
Diffstat (limited to 'tests/base.at')
-rw-r--r-- | tests/base.at | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/tests/base.at b/tests/base.at index 63bd36e7..cbc5a598 100644 --- a/tests/base.at +++ b/tests/base.at @@ -342,7 +342,7 @@ my_cv_variable=true AC_MSG_RESULT([$my_cv_variable]) # Ensure that the result is available at this point. -if test ${my_cv_variable+set} != set; then +if ${my_cv_variable+false} :; then AC_MSG_ERROR([AC@&@&t@t@_CACHE_VAL did not ensure that the cache variable was set]) fi |