diff options
Diffstat (limited to 'doc/exec.n')
| -rw-r--r-- | doc/exec.n | 71 |
1 files changed, 33 insertions, 38 deletions
@@ -6,7 +6,7 @@ '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" -'\" RCS: @(#) $Id: exec.n,v 1.15 2006/12/04 23:13:20 dkf Exp $ +'\" RCS: @(#) $Id: exec.n,v 1.16 2007/07/04 13:51:29 dkf Exp $ '\" .so man.macros .TH exec n 8.5 Tcl "Tcl Built-In Commands" @@ -185,7 +185,6 @@ If the name contains a slash then it must refer to an executable reachable from the current directory. No ``glob'' expansion or other shell-like substitutions are performed on the arguments to commands. - .SH "PORTABILITY ISSUES" .TP \fBWindows\fR (all versions) @@ -196,12 +195,13 @@ application will hang and a 32-bit application will return immediately with end-of-file. When either type of application writes to a socket, the information is instead sent to the console, if one is present, or is discarded. -.sp +.RS +.PP The Tk console text widget does not provide real standard IO capabilities. Under Tk, when redirecting from standard input, all applications will see an immediate end-of-file; information redirected to standard output or standard error will be discarded. -.sp +.PP Either forward or backward slashes are accepted as path separators for arguments to Tcl commands. When executing an application, the path name specified for the application may also contain forward or backward slashes @@ -212,12 +212,12 @@ path name with forward slashes will not automatically be converted to use the backslash character. If an argument contains forward slashes as the path separator, it may or may not be recognized as a path name, depending on the program. -.sp +.PP Additionally, when calling a 16-bit DOS or Windows 3.X application, all path names must use the short, cryptic, path format (e.g., using ``applba~1.def'' instead of ``applbakery.default''), which can be obtained with the \fBfile attributes $fileName -shortname\fR command. -.sp +.PP Two or more forward or backward slashes in a row in a path refer to a network path. For example, a simple concatenation of the root directory \fBc:/\fR with a subdirectory \fB/windows/system\fR will yield @@ -226,25 +226,29 @@ point called \fBsystem\fR on the machine called \fBwindows\fR (and the \fBc:/\fR is ignored), and is not equivalent to \fBc:/windows/system\fR, which describes a directory on the current computer. The \fBfile join\fR command should be used to concatenate path components. -.sp -.RS +.PP Note that there are two general types of Win32 console applications: .RS -1) CLI -- CommandLine Interface, simple stdio exchange. \fBnetstat.exe\fR for +.TP +1) CLI +. +CommandLine Interface, simple stdio exchange. \fBnetstat.exe\fR for example. -.br -2) TUI -- Textmode User Interface, any application that accesses the console +.TP +2) TUI +. +Textmode User Interface, any application that accesses the console API for doing such things as cursor movement, setting text color, detecting key presses and mouse movement, etc. An example would be \fBtelnet.exe\fR from Windows 2000. These types of applications are not common in a windows environment, but do exist. .RE +.PP \fBexec\fR will not work well with TUI applications when a console is not present, as is done when launching applications under wish. It is desirable to have console applications hidden and detached. This is a designed-in limitation as \fBexec\fR wants to communicate over pipes. The Expect extension addresses this issue when communicating with a TUI application. -.sp .RE .TP \fBWindows NT\fR @@ -255,26 +259,23 @@ the name as it was specified. Then, in order, \fB.com\fR, \fB.exe\fR, and for the longer name. If a directory name was not specified as part of the application name, the following directories are automatically searched in order when attempting to locate the application: -.sp -.RS .RS +.IP \(bu The directory from which the Tcl executable was loaded. -.br +.IP \(bu The current directory. -.br +.IP \(bu The Windows NT 32-bit system directory. -.br +.IP \(bu The Windows NT 16-bit system directory. -.br +.IP \(bu The Windows NT home directory. -.br +.IP \(bu The directories listed in the path. -.RE -.sp +.PP In order to execute shell built-in commands like \fBdir\fR and \fBcopy\fR, the caller must prepend the desired command with ``\fBcmd.exe /c\0\fR'' because built-in commands are not implemented using executables. -.sp .RE .TP \fBWindows 9x\fR @@ -285,31 +286,29 @@ the name as it was specified. Then, in order, \fB.com\fR, \fB.exe\fR, and for the longer name. If a directory name was not specified as part of the application name, the following directories are automatically searched in order when attempting to locate the application: -.sp -.RS .RS +.IP \(bu The directory from which the Tcl executable was loaded. -.br +.IP \(bu The current directory. -.br +.IP \(bu The Windows 9x system directory. -.br +.IP \(bu The Windows 9x home directory. -.br +.IP \(bu The directories listed in the path. -.RE -.sp +.PP In order to execute shell built-in commands like \fBdir\fR and \fBcopy\fR, the caller must prepend the desired command with ``\fBcommand.com /c\0\fR'' because built-in commands are not implemented using executables. -.sp +.PP Once a 16-bit DOS application has read standard input from a console and then quit, all subsequently run 16-bit DOS applications will see the standard input as already closed. 32-bit applications do not have this problem and will run correctly, even after a 16-bit DOS application thinks that standard input is closed. There is no known workaround for this bug at this time. -.sp +.PP Redirection between the \fBNUL:\fR device and a 16-bit application does not always work. When redirecting from \fBNUL:\fR, some applications may hang, others will get an infinite stream of ``0x01'' bytes, and some will actually @@ -317,7 +316,7 @@ correctly get an immediate end-of-file; the behavior seems to depend upon something compiled into the application itself. When redirecting greater than 4K or so to \fBNUL:\fR, some applications will hang. The above problems do not happen with 32-bit applications. -.sp +.PP All DOS 16-bit applications are run synchronously. All standard input from a pipe to a 16-bit DOS application is collected into a temporary file; the other end of the pipe must be closed before the 16-bit DOS application @@ -327,7 +326,7 @@ must terminate before the temporary files are redirected to the next stage of the pipeline. This is due to a workaround for a Windows 95 bug in the implementation of pipes, and is how the standard Windows 95 DOS shell handles pipes itself. -.sp +.PP Certain applications, such as \fBcommand.com\fR, should not be executed interactively. Applications which directly access the console window, rather than reading from their standard input and writing to their standard @@ -337,7 +336,6 @@ console window is not available to them. .TP \fBUnix\fR\0\0\0\0\0\0\0 The \fBexec\fR command is fully functional and works as described. - .SH "UNIX EXAMPLES" Here are some examples of the use of the \fBexec\fR command on Unix. .PP @@ -379,7 +377,6 @@ this: .CS \fBexec\fR ls -l {*}[glob *.tcl] .CE -.PP .SH "WINDOWS EXAMPLES" Here are some examples of the use of the \fBexec\fR command on Windows. .PP @@ -419,9 +416,7 @@ the \fBglob\fR command.) To do that, use this: .CS \fBexec\fR {*}[auto_execok dir] *.tcl .CE - .SH "SEE ALSO" error(n), open(n) - .SH KEYWORDS execute, pipeline, redirection, subprocess |