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New public macros AC_LOG_CMD and AC_LOG_FILE.

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AC_LOG_CMD is the same as the undocumented AC_RUN_LOG, which has
existed for a very long time, renamed for consistency with
AC_LOG_FILE, which is a generalization of _AC_MSG_LOG_CONFTEST.

(Not actually implemented yet; do not merge)
This commit is contained in:
Zack Weinberg 2024-06-23 22:15:20 -04:00
parent ec192f7fc9
commit 0194cf62f3
1 changed files with 59 additions and 0 deletions
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doc/autoconf.texi
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@ -440,6 +440,7 @@ Results of Tests
* Special Chars in Variables:: Characters to beware of in variables
* Caching Results:: Speeding up subsequent @command{configure} runs
* Printing Messages:: Notifying @command{configure} users
* Logging:: Recording test details in @file{config.log}
Caching Results
@ -9164,6 +9165,11 @@ write new ones. These macros are the building blocks. They provide
ways for other macros to check whether various kinds of features are
available and report the results.
The macros described in this chapter are mainly useful for tests that
involve compiling code. To write tests that simply probe the shell
environment, use M4sh; see @ref{Programming in M4sh}. Take care to
log errors output by such tests; see @ref{Logging}.
This chapter contains some suggestions and some of the reasons why the
existing tests are written the way they are. You can also learn a lot
about how to write Autoconf tests by looking at the existing ones. If
@ -10037,6 +10043,7 @@ print a message letting the user know the result of the test.
* Special Chars in Variables:: Characters to beware of in variables
* Caching Results:: Speeding up subsequent @command{configure} runs
* Printing Messages:: Notifying @command{configure} users
* Logging:: Recording test details in @file{config.log}
@end menu
@node Defining Symbols
@ -10687,6 +10694,58 @@ make hard links}.
@end defmac
@node Logging
@section Logging Details of Tests
It is helpful to record details of @emph{why} each test got the result
that it did, in @file{config.log}. The macros that compile test
programs (@code{AC_COMPILE_IFELSE} etc.; @pxref{Writing Tests}) do this
automatically, but if you write a test that only involves M4sh and basic
shell commands, you will need to do it yourself, using the following macros.
@anchor{AC_LOG_CMD}
@defmac AC_LOG_CMD (@var{shell-command})
Execute @var{shell-command}.
Record @var{shell-command} in @file{config.log}, along with any error
messages it printed (specifically, everything it wrote to its standard
error) and its exit code.
This macro may be used within a command substitution, or as the test
argument of @code{AS_IF} or a regular shell @code{if} statement.
@end defmac
@anchor{AC_LOG_FILE}
@defmac AC_LOG_FILE (@var{file}, @var{label})
Record the contents of @var{file} in @file{config.log}, labeled with
@var{label}.
@end defmac
Here is an example of how to use these macros to test for a feature of
the system `awk'.
@smallexample
AC_PROG_AWK
AC_MSG_CHECKING([whether $AWK supports 'asort'])
cat > conftest.awk <<\EOF
[@{ lines[NR] = $0 @}
END @{
ORS=" "
asort(lines)
for (i in lines) @{
print lines[i]
@}
@}]
EOF
AS_IF([result=`AC_LOG_CMD([printf 'z\ny\n' | $AWK -f conftest.awk])` &&
test x"$result" = x"y z"],
[AWK_HAS_ASORT=yes],
[AWK_HAS_ASORT=no
AC_LOG_FILE([conftest.awk], [test awk script])])
AC_MSG_RESULT([$AWK_HAS_ASORT])
AC_SUBST([AWK_HAS_ASORT])
rm -f conftest.awk
@end smallexample
@c ====================================================== Programming in M4.