URL:
<https://savannah.gnu.org/bugs/?55720>
Summary: Make cannot execute shell-builtin commands in recipe
Project: make
Submitted by: masahiroy
Submitted on: Sat 16 Feb 2019 10:11:05 AM UTC
Severity: 3 - Normal
Item Group: None
Status: None
Privacy: Public
Assigned to: None
Open/Closed: Open
Discussion Lock: Any
Component Version: None
Operating System: None
Fixed Release: None
Triage Status: None
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Details:
To print the install path of a command,
you can use 'which', 'command -v', etc.
They work in the same way:
$ which gcc
/usr/bin/gcc
$ command -v gcc
/usr/bin/gcc
'command' is included in POSIX, but 'which' is not.
So, if you want to write as portable code as possible
you may prefer 'command -v'.
However, 'command -v' does not work in Makefile
because it is a shell-builtin command.
People generally expect recipe lines are executed in a shell.
In fact, Make skips spawning a shell for optimization in some cases.
Beginners who are unfamiliar with this Make-internal may wonder why.
I attached a test Makefile.
$ make all
which gcc
/usr/bin/gcc
$ make all2
command -v gcc
make: command: Command not found
Makefile:6: recipe for target 'all2' failed
make: *** [all2] Error 127
$ make all3
: ~; command -v gcc
/usr/bin/gcc
$(shell command -v gcc) does not work either.
Probably for the same reason.
Is this a bug that should be fixed?
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File Attachments:
-------------------------------------------------------
Date: Sat 16 Feb 2019 10:11:05 AM UTC Name: Makefile Size: 189B By:
masahiroy
<http://savannah.gnu.org/bugs/download.php?file_id=46278>
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