diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/manual.asciidoc | 30 |
1 files changed, 24 insertions, 6 deletions
diff --git a/doc/manual.asciidoc b/doc/manual.asciidoc index 003c71e..4d0727e 100644 --- a/doc/manual.asciidoc +++ b/doc/manual.asciidoc @@ -778,11 +778,9 @@ A `rule` block contains a list of `key = value` declarations that affect the processing of the rule. Here is a full list of special keys. -`command` (_required_):: the command line to run. This string (after - $variables are expanded) is passed directly to `sh -c` without - interpretation by Ninja. Each `rule` may have only one `command` - declaration. To specify multiple commands use `&&` (or similar) to - concatenate operations. +`command` (_required_):: the command line to run. Each `rule` may + have only one `command` declaration. See <<ref_rule_command,the next + section>> for more details on quoting and executing multiple commands. `depfile`:: path to an optional `Makefile` that contains extra _implicit dependencies_ (see <<ref_dependencies,the reference on @@ -850,6 +848,27 @@ rule link build myapp.exe: link a.obj b.obj [possibly many other .obj files] ---- +[[ref_rule_command]] +Interpretation of the `command` variable +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +Fundamentally, command lines behave differently on Unixes and Windows. + +On Unixes, commands are arrays of arguments. The Ninja `command` +variable is passed directly to `sh -c`, which is then responsible for +interpreting that string into an argv array. Therefore the quoting +rules are those of the shell, and you can use all the normal shell +operators, like `&&` to chain multiple commands, or `VAR=value cmd` to +set environment variables. + +On Windows, commands are strings, so Ninja passes the `command` string +directly to `CreateProcess`. (In the common case of simply executing +a compiler this means there is less overhead.) Consequently the +quoting rules are deterimined by the called program, which on Windows +are usually provided by the C library. If you need shell +interpretation of the command (such as the use of `&&` to chain +multiple commands), make the command execute the Windows shell by +prefixing the command with `cmd /c`. + [[ref_dependencies]] Build dependencies ~~~~~~~~~~~~~~~~~~ @@ -947,4 +966,3 @@ Variable declarations indented in a `build` block are scoped to the 5. Variables from the file that included that file using the `subninja` keyword. - |