X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=run-command.h;h=debe3074b5a01fb5a19e61f07ff66c250cdc4f82;hb=6abf189506712a0e3c5ea796d136177b8f24ca22;hp=94e1e9d516887d818f99f8f6d6b3ded3f3be6d6f;hpb=3e4bb087a18435b12eb82116e93af2887578e816;p=git.git

diff --git a/run-command.h b/run-command.h
index 94e1e9d51..debe3074b 100644
--- a/run-command.h
+++ b/run-command.h
@@ -14,15 +14,32 @@ enum {
 struct child_process {
 	const char **argv;
 	pid_t pid;
+	/*
+	 * Using .in, .out, .err:
+	 * - Specify 0 for no redirections (child inherits stdin, stdout,
+	 *   stderr from parent).
+	 * - Specify -1 to have a pipe allocated as follows:
+	 *     .in: returns the writable pipe end; parent writes to it,
+	 *          the readable pipe end becomes child's stdin
+	 *     .out, .err: returns the readable pipe end; parent reads from
+	 *          it, the writable pipe end becomes child's stdout/stderr
+	 *   The caller of start_command() must close the returned FDs
+	 *   after it has completed reading from/writing to it!
+	 * - Specify > 0 to set a channel to a particular FD as follows:
+	 *     .in: a readable FD, becomes child's stdin
+	 *     .out: a writable FD, becomes child's stdout/stderr
+	 *     .err > 0 not supported
+	 *   The specified FD is closed by start_command(), even in case
+	 *   of errors!
+	 */
 	int in;
 	int out;
 	int err;
 	const char *dir;
 	const char *const *env;
-	unsigned close_in:1;
-	unsigned close_out:1;
 	unsigned no_stdin:1;
 	unsigned no_stdout:1;
+	unsigned no_stderr:1;
 	unsigned git_cmd:1; /* if this is to be git sub-command */
 	unsigned stdout_to_stderr:1;
 };