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Diffstat (limited to 'doc/make.texi')
| -rw-r--r-- | doc/make.texi | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/doc/make.texi b/doc/make.texi index 2aacc70..3a873d7 100644 --- a/doc/make.texi +++ b/doc/make.texi @@ -6321,6 +6321,28 @@ will contain the number of times this instance has restarted. Note this is not the same as recursion (counted by the @code{MAKELEVEL} variable). You should not set, modify, or export this variable. +@vindex MAKE_TTYOUT @r{(whether stdout is a terminal)} +@vindex MAKE_TTYERR @r{(whether stderr is a terminal)} +@item MAKE_TTYOUT +@itemx MAKE_TTYERR +When @code{make} starts it will check whether stdout and stderr will +show their output on a terminal. If so, it will set +@code{MAKE_TTYOUT} and @code{MAKE_TTYERR}, respectively, to the name +of the terminal device (or @code{true} if this cannot be determined). +If set these variables will be marked for export. These variables +will not be changed by @code{make} and they will not be modified if +already set. + +These values can be used (particularly in combination with output +synchronization (@pxref{Parallel Output, ,Output During Parallel +Execution}) to determine whether @code{make} itself is writing to a +terminal; they can be tested to decide whether to force recipe +commands to generate colorized output for example. + +If you invoke a sub-@code{make} and redirect its stdout or stderr it +is your responsibility to reset or unexport these variables as well, +if your makefiles rely on them. + @vindex .RECIPEPREFIX @r{(change the recipe prefix character)} @item .RECIPEPREFIX The first character of the value of this variable is used as the |