X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fpipecmd%2Fpipecmd.h;h=5bbaefc01234699e23ab719d2495161f9ae1b935;hp=4816950502f2c949183ea72fcaacb60976a995cb;hb=d3d2242ba8d975f8d7ddaa0348953dfd6f45ffce;hpb=440efa555b08324386fa15488cefaed68a791d6e

diff --git a/ccan/pipecmd/pipecmd.h b/ccan/pipecmd/pipecmd.h
index 48169505..5bbaefc0 100644
--- a/ccan/pipecmd/pipecmd.h
+++ b/ccan/pipecmd/pipecmd.h
@@ -18,6 +18,7 @@
  * If @errfd is NULL, the child's stderr is (write-only) /dev/null.
  *
  * If @errfd == @outfd (and non-NULL) they will be shared.
+ * If @infd, @outfd or @errfd is &pipecmd_preserve, it is unchanged.
  *
  * The return value is the pid of the child, or -1.
  */
@@ -41,4 +42,10 @@ pid_t pipecmdv(int *infd, int *outfd, int *errfd, const char *cmd, va_list ap);
  * @arr: NULL-terminated array for arguments (first is program to run).
  */
 pid_t pipecmdarr(int *infd, int *outfd, int *errfd, char *const *arr);
+
+/**
+ * pipecmd_preserve - special value for fds to indicate it is unchanged
+ */
+extern int pipecmd_preserve;
+
 #endif /* CCAN_PIPECMD_H */