diff options
Diffstat (limited to 'man/3')
| -rw-r--r-- | man/3/cmd | 15 |
1 files changed, 11 insertions, 4 deletions
@@ -10,6 +10,8 @@ cmd \- interface to host operating system commands .br .BI /cmd/ n /data .br +.BI /cmd/ n /stderr +.br .BI /cmd/ n /status .br .BI /cmd/ n /wait @@ -69,9 +71,11 @@ Spawn a host process to run the with arguments as given. The write returns with an error, setting the error string, if anything prevents starting the command. -If write returns successfully, the command has started, and its input and +If write returns successfully, the command has started, and its standard input and output may be accessed through -.B data +.BR data , +and its error output accessed through +.B stderr (see below). If arguments containing white space are quoted (following the conventions of .IR sh (1) @@ -105,14 +109,17 @@ The file provides a connection to the input and output of a previously-started host command. It must be opened separately for reading and for writing. -When opened for reading, it returns data that the command writes to its standard output and standard error (the -streams are merged); when closed, further writes by the command will receive the host +When opened for reading, it returns data that the command writes to its standard output; when closed, further writes by the command will receive the host equivalent of `write to closed pipe'. When opened for writing, data written to the file can be read by the command on its standard input; when closed, further reads by the command will see the host equivalent of `end of file'. (Unfortunately there is no way to know when the command needs input.) .PP +The +.B stderr +file provides a similar read-only connection to the error output from the command. +.PP Once started, a host command runs until it terminates or until it is killed, by using the .B kill |