Andrew L. Moore wrote:
Here, ed reads from named pipe `<(cal)' to the editor buffer
[...]
GNU ed is not able to read from named pipes like that;
I have been looking into this and it seems like a bug in the system, maybe
in the compiler, because:
- I copied the relevant code from moe, where 'moe <(cal)' has always worked.
- if I compile ed with g++, 'ed <(cal)' works.
- if I run 'valgrind ed <(cal)' also works.
This is the code causing the trouble (lines 288-291 of io.c):
if( *filename == '!' ) fp = popen( filename + 1, "r" );
else if( !( fp = fopen( filename, "r+" ) ) && errno != ENOENT &&
( fp = fopen( filename, "r" ) ) && read_onlyp && !modified() )
*read_onlyp = true;
In particular the 'fopen( filename, "r+" )' causes the output pipe from
'cal' not to close, causing the 'getc' in ed to block instead of returning
EOF. I have not yet found a satisfactory workaround that a) does not block
and b) sets read_only correctly.
GNU ed is not able to filter buffer lines via external commands;
I have already implemented the ex-style filter. I'll release it as soon as I
find the time to do so.
Best regards,
Antonio.
